阅读说明：本技术 一种辅助动力装置进气门控制系统及方法 (Auxiliary power device air inlet valve control system and method ) 是由 张宝升 杨恒辉 王超 王浩 徐杰 于 2020-05-27 设计创作，主要内容包括：本发明属于辅助动力装置控制领域,尤其涉及一种辅助动力装置进气门控制系统及方法,克服在空中状态下,由于高马赫数及较低的APU进口压力导致的进入APU的气流极不稳定,从而造成APU点火不成功的问题,本发明中,当驾驶舱的“APU主开关”被按下时,ECU通电,在地面状态下,在收到APU起动指令后,也是直接将进气门全开,然后起动APU。但在空中状态下,ECU会按照预定的与飞行马赫数、APU转速、APU进口压力的函数关系f(Ma,N,P2)将进气门逐渐打开,使得进入APU的气流相对稳定。本发明不仅可以准确控制APU进气门的打开或关闭,还可以控制打开的开度,进而调节进入APU燃烧室的进气量并显著提高APU点火成功率,可应用于飞行包线宽、使用工况复杂的APU进气门控制。(The invention belongs to the field of auxiliary power device control, and particularly relates to an auxiliary power device air inlet valve control system and method, which overcome the problem that in an air state, airflow entering an APU is extremely unstable due to high Mach number and low APU inlet pressure, so that the ignition of the APU is unsuccessful. However, in the air state, the ECU gradually opens the intake valve according to a preset functional relation f (Ma, N, P2) with flight Mach number, APU rotating speed and APU inlet pressure, so that the airflow entering the APU is relatively stable. The invention can accurately control the opening or closing of the APU inlet valve and can also control the opening degree of the APU inlet valve, thereby regulating the air input amount entering the APU combustion chamber and obviously improving the ignition success rate of the APU, and can be applied to the control of the APU inlet valve with wide flight envelope and complex use working conditions.)

1. An auxiliary power unit intake valve control system comprises an APU electronic controller and an intake valve actuating mechanism;

the method is characterized in that:

the intake valve actuating mechanism comprises a motor, an actuating connecting rod mechanism and a position sensor; the motor is used for controlling the position of the intake valve through the actuating link mechanism according to a control instruction output by the APU electronic controller; the position sensor is used for acquiring an air inlet valve position signal and feeding back the real-time position signal of the air inlet valve to the APU electronic controller in real time;

the APU electronic controller comprises a CPU, an opening driving circuit, a closing driving circuit and a position signal decoding circuit;

the opening driving circuit and the closing driving circuit are respectively used for outputting an inlet valve opening driving and an inlet valve closing driving according to a control instruction output by the CPU; the position signal decoding circuit is used for resolving an intake valve real-time position signal fed back by a position sensor in the intake valve actuating mechanism and sending the resolved intake valve real-time position signal to the CPU;

the CPU outputs a control instruction by combining the resolved real-time position signal of the intake valve according to a starting instruction of the APU, and controls the real-time position of the intake valve to be consistent with a predetermined expected position; or outputting a control command by combining the stop command of the APU and the real-time position signal of the intake valve to control the intake valve to close.

2. The auxiliary power unit intake valve control system according to claim 1, wherein:

after receiving the starting instruction of the APU:

if the airplane is on the ground, the CPU outputs a control instruction that an inlet valve is directly opened to a full-open position alpha;

if the aircraft is in the air, the CPU outputs a control command according to a predetermined functional relation f (Ma, N, P2) between the expected position of the intake valve and the flight Mach number Ma, the rotation speed N of the APU and the inlet pressure P2 of the APU, so that the real-time position of the intake valve is consistent with the expected position of the current intake valve under the current flight Mach number Ma, the rotation speed N of the APU and the inlet pressure P2 of the APU;

after receiving an APU normal parking instruction:

and when the received calculated real-time position of the intake valve reaches the fully closed position, the CPU outputs an intake valve opening cutting driving control instruction.

3. The auxiliary power unit intake valve control system according to claim 2, wherein: the APU electronic controller also comprises a first open circuit detection circuit, a first overcurrent detection circuit, a second open circuit detection circuit and a second overcurrent detection circuit;

the first open circuit detection circuit is connected in series between the opening drive circuit and the CPU and is used for detecting whether the motor is open or not in the process of opening drive output of the inlet valve;

the first overcurrent detection circuit is connected in series between the opening drive circuit and the CPU and is used for detecting whether the motor is in overcurrent or not in the opening drive output process of the inlet valve;

the second open-circuit detection circuit is connected in series between the closing drive circuit and the CPU and is used for detecting whether the motor is open-circuit or not in the closing drive output process of the inlet valve;

and the second overcurrent detection circuit is connected in series between the closing drive circuit and the CPU and is used for detecting whether the motor is in overcurrent or not in the closing drive output process of the intake valve.

4. The auxiliary power unit intake valve control system according to claim 3, wherein:

the inlet valve actuating mechanism also comprises a full-open position switch, an opening limit switch, a full-close position switch and a closing limit switch;

the APU electronic controller also comprises a discrete quantity input interface circuit and a power supply output circuit; the discrete quantity input interface circuit comprises a full-open position switch signal receiving end, an air inlet valve moving signal receiving end and a full-close position switch signal receiving end, and is respectively used for receiving a full-open position switch signal, an air inlet valve moving signal and a full-close position switch signal output by an air inlet valve actuating mechanism and feeding back the full-open position switch signal, the air inlet valve moving signal and the full-close position switch signal to the CPU; the power supply output circuit is used for outputting an intake valve indication power supply signal;

the full-open position switch and the open limit switch are linked switches; the fixed end of the full-open position switch is connected with a signal receiving end of the full-open position switch in the discrete quantity input interface circuit of the APU electronic controller, one side of the movable end is grounded, and the other side of the movable end is connected with the output end of a power supply output circuit of the APU electronic controller; the fixed end of the opening limit switch is connected with the output end of an opening drive circuit of an APU electronic controller, one side of the movable end is connected with a motor and an inlet valve moving signal receiving end in a discrete quantity input interface circuit of the APU electronic controller, and the other side of the movable end is disconnected;

the fully-closed position switch and the closing limit switch are linkage switches; the fixed end of the full-off position switch is connected with a signal receiving end of the full-off position switch of the discrete quantity input interface circuit of the APU electronic controller, one side of the moving end is grounded, and the other side of the moving end is connected with the output end of a power supply output circuit of the APU electronic controller; and the fixed end of the closing limit switch is connected with the output end of the closing drive circuit of the APU electronic controller, one side of the movable end is connected with the motor and the inlet valve moving signal receiving end in the discrete magnitude input interface circuit of the APU electronic controller, and the other side of the movable end is disconnected.

5. The auxiliary power unit intake valve control system according to claim 4, wherein: the intake valve actuating mechanism also comprises an MCU, a position signal feedback circuit, a drive detection circuit, an output signal conditioning circuit and a fault signal output circuit;

the position signal feedback circuit is used for conditioning the position signal of the intake valve acquired by the position sensor and sending the conditioned and converted position signal of the intake valve to a position signal decoding circuit in an APU electronic controller;

the driving detection circuit is used for detecting whether the voltage of the intake valve opening driving or the intake valve closing driving output by the APU electronic controller is normal or not; and feeding back to the MCU; the MCU controls the actions of opening and closing the limit switch according to the feedback result;

the output signal conditioning circuit is used for conditioning a full-open position switch signal, a full-close position switch signal and an inlet valve movement signal which are fed back to the APU electronic controller;

and the fault signal output circuit is used for sending self fault information detected by the actuating mechanism of the intake valve to an APU electronic controller or other fault recording equipment.

6. The control method of the intake valve of the auxiliary power device is characterized by comprising the following processing procedures:

step 1, determining an expected position of an intake valve;

when the aircraft is on the ground:

the expected opening position of the intake valve is a full opening position alpha, and alpha is the maximum opening degree of the intake valve;

the desired position of the intake valve closing is a fully closed position;

when the airplane is in the air:

the expected positions of the opening of the intake valve comprise a plurality of expected positions which are respectively m-th expected positions of the first expected position … …, wherein the expected positions are the functional relations f (Ma, N, P2) of flight Mach number Ma, APU rotating speed N and APU inlet pressure P2, and each expected position corresponds to a different range of APU rotating speed N under the condition of the same flight Mach number Ma and the same APU inlet pressure P2; wherein m is a positive integer greater than or equal to 1;

the desired position of the intake valve closing is a fully closed position;

step 2, controlling the opening of an intake valve;

2.1) the APU electronic controller completes self-checking before starting, and immediately outputs an inlet valve opening drive after receiving an APU starting instruction;

2.2) controlling a motor of the actuating mechanism of the inlet valve to rotate positively;

if the aircraft is on the ground: controlling an intake valve to be directly opened to a full-open position alpha;

if the airplane is in the air, and the flight Mach number Ma, the APU rotating speed N and the APU inlet pressure P2 are in the numerical range corresponding to the first expected position of the opening of the intake valve, the opening driving of the intake valve is cut off when the position sensor of the intake valve actuating mechanism feeds back that the intake valve reaches the first expected position;

when the rotation speed N of the APU rises to exceed the rotation speed numerical range corresponding to the first expected position of the opening of the intake valve and is positioned in the numerical range corresponding to the second expected position of the opening of the intake valve, the APU electronic controller outputs the opening drive of the intake valve again until the position sensor feeds back that the intake valve reaches the second expected position, and the opening drive of the intake valve is cut off;

repeating the steps until the position sensor feeds back the intake valve to the full-open position;

step 3, closing control of an intake valve;

3.1) when the APU electronic controller receives the APU normal stop instruction, the rotation speed of the APU is reduced to N_dImmediately outputting an intake valve closing drive when the engine is started; wherein N is_dA stop operation rotating speed decision point of the APU is set;

3.2) the motor of the air inlet valve actuating mechanism rotates reversely until the position sensor feeds back that the air inlet valve reaches the full-closed position, and the driving is cut off.

7. The auxiliary power unit intake valve control method according to claim 6, characterized in that: the output time of each intake valve opening drive is less than or equal to t₁(ii) a When the APU electronic controller outputs an intake valve opening drive of t₁During the time, if the air inlet valve does not reach the expected position, stopping outputting the air inlet valve opening drive;

the output time of each intake valve closing drive is less than or equal to t₁(ii) a When the APU electronic controller outputs an intake valve closing drive of t₁During the time, if the intake valve has not reached the fully closed position, the output of the intake valve closing drive is stopped.

8. The auxiliary power unit intake valve control method according to claim 7, characterized in that: in the step 2, in the working process of the motor, an APU electronic controller monitors whether the motor is in overcurrent or not; when the motor overflows, the APU electronic controller stops outputting the opening drive of the inlet valve and waits for time t_wAnd then trying to output the opening drive of the intake valve again, if the opening drive of the intake valve is output for n times of continuous overflowing, not outputting the opening drive of the intake valve, and reporting the overflowing fault of the opening drive of the intake valve, wherein the overflowing time n is t_1/t_wWherein n is an integer.

9. The intake valve control method of the auxiliary power unit according to any one of claims 6 to 8, characterized in that: in step 2.2, when the air inlet valve is opened, if a position sensor of the air inlet valve actuating mechanism fails, the air inlet valve opening drive is cut off when a full-opening position switch feeds back a full-opening signal to an APU electronic controller until the air inlet valve is opened to a full-opening position, and meanwhile, the air inlet valve opening drive is cut off when a limit switch is opened; and if the position sensor, the full-open position switch and the open limit switch simultaneously fail, stopping outputting the opening drive of the inlet valve.

10. The auxiliary power unit intake valve control method according to claim 9, characterized in that: step 3, in the working process of the motor, an APU electronic controller monitors whether the motor is in overcurrent or not; when the motor is in overcurrent, the APU electronic controllerStopping output of intake valve closing drive for waiting time t_wAnd then trying to output the intake valve closing drive again, if the engine is subjected to continuous n times of overcurrent, not outputting the intake valve closing drive again, and reporting the overcurrent fault of the intake valve closing drive, wherein the overcurrent time n is t_1/t_wWherein n is an integer.

11. The auxiliary power unit intake valve control method according to claim 10, characterized in that: in step 3.2, when the air inlet valve is closed, if the position sensor fails, the air inlet valve is cut off from the closing drive when the fully closed position switch feeds back a fully closed signal to an APU electronic controller until the air inlet valve is closed to the fully closed position, and meanwhile, the closing limit switch also cuts off the closing drive of the air inlet valve; when the position sensor, the full-off position switch and the closing limit switch simultaneously fail, the APU electronic controller outputs an inlet valve closing drive t₂Time-wise cut-off of the drive, where t₂The minimum time required for the intake valve to move to full stroke, t₂Less than t₁。

12. The auxiliary power unit intake valve control method according to claim 11, characterized in that: 2.2, the APU electronic controller feeds back the position information, the fully-open position switch state and the minimum time t required for the air inlet valve to move to the full stroke through the position sensor₂Determining whether the air inlet valve reaches the full open position, and when the following two conditions are met, determining that the air inlet valve is fully open, wherein a1 and the position sensor work normally, and the opening of the air inlet valve is more than or equal to α₁(ii) a b1, the fully-opened position switch works normally and indicates that the inlet valve is fully opened; c1, intake valve opening drive output t₂The above.

13. The auxiliary power unit intake valve control method according to claim 12, characterized in that: 3.2, the APU electronic controller can feed back the position information through the position sensor, the fully closed position switch state and the shortest time t required for the air inlet valve to move to the full stroke₂To judge whether the air inlet valve reaches the full-closed position, when the following two are satisfiedIn the condition, a2 and the position sensor work normally, and the opening of the air inlet valve is less than or equal to α₂(ii) a b2, the full-open position switch works normally and indicates that the inlet valve is fully closed; c2, intake valve opening drive output t₂The above.

14. The auxiliary power unit intake valve control method according to claim 9, characterized in that:

the method also comprises the following steps between the steps 2.1) and 2.2): a driving detection circuit in the air inlet valve actuating mechanism detects whether the voltage of the air inlet valve opening driving output by the APU electronic controller is normal or not, and if the voltage is normal, an opening limit switch is switched on;

the method also comprises the following steps between the steps 3.1) and 3.2): and a driving detection circuit in the air inlet valve actuating mechanism detects whether the voltage of the air inlet valve closing drive output by the APU electronic controller is normal or not, and if the voltage is normal, a closing limit switch is switched on.

Technical Field

The invention belongs to the field of auxiliary power device control, and relates to a gas turbine engine, in particular to control of an air inlet valve of an auxiliary power device.

Background

An Auxiliary Power Unit (APU) is an Auxiliary Power source of an airplane, and a core Unit of the APU is a small centrifugal gas turbine engine. The system is mainly used for providing bleed air for a starting and environment control system of a main engine of the airplane and providing shaft power for a power generation system of the airplane through an accessory gearbox. When the airplane is on the ground, the APU can replace a heavy air source vehicle and a heavy power vehicle; in the process of taking off the airplane, the APU is used, so that the power of the main engine can be completely used for accelerating climbing, and the taking off performance of the airplane is improved; after the aircraft lands, the main engine can be shut down by using the APU, so that fuel is saved and airport noise is reduced. Modern large and medium sized aircraft are therefore all equipped with APUs.

The function of the APU inlet valve is as follows: firstly, foreign matters can be prevented from entering an air inlet channel when the APU does not work, and the APU is prevented from sucking the foreign matters during running so as to prevent destructive damage; secondly, the air input amount entering the APU combustion chamber can be controlled through the opening degree so as to obtain the optimal ignition condition and improve the ignition success rate to the maximum extent.

The APU air inlet valve control system comprises an APU Electronic Controller (ECU) and an air inlet valve actuating mechanism, and is used for controlling the opening and closing of an APU air inlet valve on the ground and in the air. And the ECU sends an opening or closing instruction of the intake valve according to the operation mode of the APU, the actuating mechanism completes operation according to the instruction, and feeds back the state and position information of the intake valve in real time, so that closed-loop control of the intake valve is completed.

The control of the intake valve of the APU is an important function of the control of the APU, if the intake valve is not opened, the APU is started, if the intake valve is not opened, the starting is not successful, and if the intake valve is not opened, the overheat and surge of the APU are caused, so that the APU is seriously damaged. The general control method is as follows: when an 'APU main switch' of a cockpit is pressed, the ECU is electrified, after an APU starting instruction is received, the air inlet valve is directly opened fully, and then the APU is started. Under the ground state, the control method is feasible; in an aerial state, particularly around 7km high altitude, airflow entering the APU is extremely unstable due to high Mach number and low APU inlet pressure, and if an inlet valve is fully opened, violent airflow can cause unsuccessful ignition of the APU, so that the starting success rate is reduced, and the flight safety of an airplane is influenced.

Disclosure of Invention

The invention aims to provide a novel control method for an air inlet valve of an auxiliary power device, which aims to overcome the problem that the ignition of an APU is unsuccessful due to extremely unstable airflow entering the APU caused by high Mach number and low APU inlet pressure in an air state. However, in the air state, the ECU gradually opens the intake valve according to a predetermined functional relation f (Ma, N, P2) with the flight Mach number, the APU rotating speed and the APU inlet pressure, so that the airflow entering the APU is relatively stable, the ignition is facilitated, the stable operation of the APU is facilitated, and the APU is prevented from flameout. The method is simple and has high reliability.

The invention provides an intake valve control system of an auxiliary power device, which comprises an APU electronic controller and an intake valve actuating mechanism;

it is characterized in that:

the intake valve actuating mechanism comprises a motor, an actuating connecting rod mechanism and a position sensor; the motor is used for controlling the position of the intake valve through the actuating link mechanism according to a control instruction output by the APU electronic controller; the position sensor is used for acquiring an air inlet valve position signal and feeding back the real-time position signal of the air inlet valve to the APU electronic controller in real time;

the APU electronic controller comprises a CPU, an opening driving circuit, a closing driving circuit and a position signal decoding circuit;

the opening driving circuit and the closing driving circuit are respectively used for outputting an inlet valve opening driving and an inlet valve closing driving according to a control instruction output by the CPU; the position signal decoding circuit is used for resolving an intake valve real-time position signal fed back by a position sensor in the intake valve actuating mechanism and sending the resolved intake valve real-time position signal to the CPU;

the CPU outputs a control instruction by combining the resolved real-time position signal of the intake valve according to a starting instruction of the APU, and controls the real-time position of the intake valve to be consistent with a predetermined expected position; or outputting a control command by combining the stop command of the APU and the real-time position signal of the intake valve to control the intake valve to close.

Further, the CPU outputs a control instruction according to the flight state of the airplane, and after receiving a starting instruction of the APU:

if the airplane is on the ground, the CPU outputs a control instruction that an inlet valve is directly opened to a full-open position alpha;

if the aircraft is in the air, the CPU outputs a control command according to a predetermined functional relation f (Ma, N, P2) between the expected position of the intake valve and the flight Mach number Ma, the rotating speed N of the APU and the inlet pressure P2 of the APU (generally an empirical data table), so that the real-time position of the intake valve is consistent with the expected position of the current intake valve under the current flight Mach number Ma, the rotating speed N of the APU and the inlet pressure P2 of the APU;

after receiving an APU normal parking instruction:

and when the received calculated real-time position of the intake valve reaches the fully closed position, the CPU outputs an intake valve opening cutting driving control instruction.

Furthermore, in order to prevent the damage to the APU electronic controller and the motor caused by overlarge current due to motor stalling, intake valve clamping stagnation and the like, the APU electronic controller also comprises a first open-circuit detection circuit, a first overcurrent detection circuit, a second open-circuit detection circuit and a second overcurrent detection circuit;

the first open circuit detection circuit is connected in series between the opening drive circuit and the CPU and is used for detecting whether the motor is open or not in the process of opening drive output of the inlet valve;

the first overcurrent detection circuit is connected in series between the opening drive circuit and the CPU and is used for detecting whether the motor is in overcurrent or not in the opening drive output process of the inlet valve;

the second open-circuit detection circuit is connected in series between the closing drive circuit and the CPU and is used for detecting whether the motor is open-circuit or not in the closing drive output process of the inlet valve;

and the second overcurrent detection circuit is connected in series between the closing drive circuit and the CPU and is used for detecting whether the motor is in overcurrent or not in the closing drive output process of the intake valve.

Furthermore, the inlet valve actuating mechanism also comprises a full-open position switch, an opening limit switch, a full-close position switch and a closing limit switch;

the APU electronic controller also comprises a discrete quantity input interface circuit and a power supply output circuit; the discrete magnitude input interface circuit comprises a full-open position switch signal receiving end, an inlet valve moving signal receiving end and a full-close position switch signal receiving end; the power supply output circuit is used for outputting an intake valve indication power supply signal;

the full-open position switch and the open limit switch are linked switches; the fixed end of the full-open position switch is connected with a signal receiving end of the full-open position switch in the discrete quantity input interface circuit of the APU electronic controller, one side of the movable end is grounded, and the other side of the movable end is connected with the output end of a power supply output circuit of the APU electronic controller; the fixed end of the opening limit switch is connected with the output end of an opening drive circuit of an APU electronic controller, one side of the movable end is connected with a motor and an inlet valve moving signal receiving end in a discrete quantity input interface circuit of the APU electronic controller, and the other side of the movable end is disconnected;

the fully-closed position switch and the closing limit switch are linkage switches; the fixed end of the full-off position switch is connected with a signal receiving end of the full-off position switch of the discrete quantity input interface circuit of the APU electronic controller, one side of the moving end is grounded, and the other side of the moving end is connected with the output end of a power supply output circuit of the APU electronic controller; and the fixed end of the closing limit switch is connected with the output end of the closing drive circuit of the APU electronic controller, one side of the movable end is connected with the motor and the inlet valve moving signal receiving end in the discrete magnitude input interface circuit of the APU electronic controller, and the other side of the movable end is disconnected.

Furthermore, the intake valve actuating mechanism also comprises an MCU, a position signal feedback circuit, a drive detection circuit, an output signal conditioning circuit and a fault signal output circuit;

the position signal feedback circuit is used for conditioning the position signal of the intake valve acquired by the position sensor and sending the conditioned and converted position signal of the intake valve to a position signal decoding circuit in an APU electronic controller;

the driving detection circuit is used for detecting whether the voltage of the intake valve opening driving or the intake valve closing driving output by the APU electronic controller is normal or not; and feeding back to the MCU; the MCU controls the actions of opening and closing the limit switch according to the feedback result;

the output signal conditioning circuit is used for conditioning a full-open position switch signal, a full-close position switch signal and an inlet valve movement signal which are fed back to the APU electronic controller;

and the fault signal output circuit is used for sending self fault information detected by the actuating mechanism of the intake valve to an APU electronic controller or other fault recording equipment.

The invention also provides a control method of the intake valve of the auxiliary power device, which is characterized by comprising the following processing procedures:

step 1, determining an expected position of an intake valve;

when the aircraft is on the ground:

the flight Mach number is 0, the APU inlet pressure is a ground constant pressure, and in order to ensure the air inflow required by the starting of the APU, the expected opening position of an air inlet valve is a full opening position alpha, and alpha is the maximum opening of the air inlet valve, as in the traditional control method;

the desired position of the intake valve closing is a fully closed position;

when the airplane is in the air:

the air intake amount of the APU is closely related to the flight Mach number, the rotation speed of the APU and the inlet pressure (height) of the APU, the expected position of the opening of the intake valve generally comprises a plurality of expected positions which are respectively the mth expected position of a first expected position … …, and the expected position is a functional relation f (Ma, N, P2) of the flight Mach number Ma, the rotation speed N of the APU and the inlet pressure P2 of the APU; wherein m is a positive integer greater than or equal to 1;

the desired position of the intake valve closing is a fully closed position;

step 2, controlling the opening of an intake valve;

2.1) the APU electronic controller completes self-checking before starting, and immediately outputs an inlet valve opening drive after receiving an APU starting instruction;

2.2) the ECU sends out an inlet valve opening drive to the inlet valve actuating mechanism to control a motor of the inlet valve actuating mechanism to rotate positively; thereby driving the output shaft to actuate and finally driving the inlet valve of the airplane to rotate and open; after the ECU outputs the opening drive of the inlet valve, the inlet valve actuating mechanism feeds back real-time position information to the ECU through the position sensor, and the ECU realizes the closed-loop control of the inlet valve through collecting the position information.

If the aircraft is on the ground: controlling an intake valve to be directly opened to a full-open position alpha;

if the airplane is in the air, and the flight Mach number Ma, the APU rotating speed N and the APU inlet pressure P2 are in the numerical range corresponding to the first expected position of the opening of the intake valve, the opening driving of the intake valve is cut off when the position sensor of the intake valve actuating mechanism feeds back that the intake valve reaches the first expected position;

when the rotation speed N of the APU rises to exceed the rotation speed numerical range corresponding to the first expected position of the opening of the intake valve and is positioned in the numerical range corresponding to the second expected position of the opening of the intake valve, the APU electronic controller outputs the opening drive of the intake valve again until the position sensor feeds back that the intake valve reaches the second expected position, and the opening drive of the intake valve is cut off;

repeating the operation of the steps until the position sensor feeds back the intake valve to the full-open position; in the starting process of the APU, the more expected position points are, the more stable the APU air intake is, but the more complex the control of the air intake valve is, when the expected position points are more than a certain number, the improvement of the starting performance of the APU is basically not influenced, therefore, the number of the expected position points is selected according to the actual situation and the complexity of the air intake valve control and the influence on the improvement of the starting performance of the APU.

Step 3, closing control of an intake valve;

3.1) in order to ensure the operation safety of the APU, when the APU electronic controller receives the normal shutdown command of the APU, the APU rotates at the speedDown to N_dImmediately outputting an intake valve closing drive when the engine is started; wherein N is_dThe method is characterized in that the method comprises the following steps of (1) considering that the APU completely stops running at a stop running rotating speed judgment point of the APU, namely below the rotating speed, and relating to the characteristics of the APU;

3.2) APU electronic controller sends the intake valve to actuate the mechanism to the intake valve and closes the drive, and the motor that the intake valve actuates the mechanism makes the antiport to drive the output shaft and actuate, finally drive the aircraft intake valve and do the rotation and close the motion, and the intake valve actuates the mechanism and feeds back real-time position information to APU electronic controller through position sensor, and APU electronic controller realizes the closed loop control of intake valve through gathering position information, cuts off the drive when the position sensor feedback intake valve reaches the position of closing entirely.

Further, to avoid damage to the APU electronic controller, the output time of each intake valve opening drive is less than or equal to t₁(ii) a When the APU electronic controller outputs an intake valve opening drive of t₁During the time, if the air inlet valve does not reach the expected position, stopping outputting the air inlet valve opening drive;

the output time of each intake valve closing drive is less than or equal to t₁(ii) a When the APU electronic controller outputs an intake valve closing drive of t₁During the time, if the intake valve has not reached the fully closed position, the output of the intake valve closing drive is stopped.

Furthermore, in the step 2, in order to prevent the damage to the APU electronic controller and the motor caused by overlarge current due to motor stalling, intake valve clamping stagnation and the like, the APU electronic controller monitors whether the motor is in overcurrent or not in the working process of the motor; the over-current point OCP is related to the motor and drive characteristics. When the motor overflows, the APU electronic controller stops outputting the opening drive of the inlet valve and waits for time t_wAnd then trying to output the opening drive of the intake valve again, if the opening drive of the intake valve is output for n times of continuous overflowing, not outputting the opening drive of the intake valve, and reporting the overflowing fault of the opening drive of the intake valve, wherein the overflowing time n is t_1/t_wWherein n is an integer.

Furthermore, in order to prevent the damage of the intake valve caused by the locked rotor, in step 2.2, when the intake valve reaches the expected position, if a position sensor of the intake valve actuating mechanism fails, the opening drive of the intake valve is cut off until the intake valve is opened to the full-open position, and when the full-open position switch feeds back a full-open signal, the full-open position switch and the opening limit switch are linkage switches. And if the position sensor, the fully-open position switch and the open limit switch simultaneously fail, stopping outputting the opening drive of the inlet valve, carrying out protective parking and forbidding the starting of the APU.

Furthermore, in order to prevent the damage to the APU electronic controller and the motor due to overlarge current caused by motor stalling, intake valve clamping stagnation and the like, in step 3, in the working process of the motor, the APU electronic controller monitors whether the motor is in overcurrent, and an overcurrent point OCP is related to the characteristics of the motor and a driver; when the motor overflows, the APU electronic controller stops outputting the closing drive of the inlet valve and waits for time t_wAnd then trying to output the intake valve closing drive again, if the engine is subjected to continuous n times of overcurrent, not outputting the intake valve closing drive again, and reporting the overcurrent fault of the intake valve closing drive, wherein the overcurrent time n is t_1/t_wWherein n is an integer.

Further, in order to prevent the damage of the intake valve caused by the locked rotor, in step 3.2, when the intake valve reaches the fully closed position, if the position sensor fails, the closing drive of the intake valve is cut off until the intake valve is closed to the fully closed position, and the fully closed position switch feeds back a fully closed signal, meanwhile, the fully closed position switch and the closing limit switch are linkage switches, and when the fully closed position switch feeds back a fully closed signal, the closing limit switch also cuts off the closing drive of the intake valve, so that a double-safety effect is achieved, and the damage of the intake valve caused by the locked rotor is prevented. When the position sensor, the full-off position switch and the closing limit switch simultaneously fail, the ECU outputs an inlet valve closing drive t₂Time-wise cut-off of the drive, where t₂The minimum time required for the intake valve to move to full stroke, t₂Less than t₁。

Further, in step 2.2, the APU electronic controller feeds back position information through the position sensorOpen position switch state and minimum time t required for intake valve to move to full stroke₂Determining whether the air inlet valve reaches the full open position, and when the following two conditions are met, determining that the air inlet valve is fully open, wherein a1 and the position sensor work normally, and the opening of the air inlet valve is more than or equal to α₁(ii) a b1, the fully-opened position switch works normally and indicates that the inlet valve is fully opened; c1, intake valve opening drive output t₂α in the above₁Is related to the mounting position and characteristics of the inlet valve and should be less than the maximum opening α of the inlet valve t₂The minimum time required for the intake valve to move to full stroke should be less than t₁。

Further, in step 3.2, the APU electronic controller can feed back the position information through the position sensor, the fully closed position switch state and the minimum time t required for the air inlet valve to move to the full stroke₂Judging whether the air inlet valve reaches the full-close position, and judging that the air inlet valve is fully closed when any two conditions are met, namely a2, the position sensor works normally, and the opening of the air inlet valve is less than or equal to α₂(ii) a b2, the full-open position switch works normally and indicates that the inlet valve is fully closed; c2, intake valve opening drive output t₂α in the above₂The value of (A) is related to the installation position and the characteristics of the inlet valve, and is generally larger than zero opening; t is t₂The minimum time required for the intake valve to move to full stroke should be less than t₁。

Further, steps 2.1) and 2.2) further include: a driving detection circuit in the air inlet valve actuating mechanism detects whether the voltage of the air inlet valve opening driving output by the APU electronic controller is normal or not, and if the voltage is normal, an opening limit switch is switched on;

the method also comprises the following steps between the steps 3.1) and 3.2): and a driving detection circuit in the air inlet valve actuating mechanism detects whether the voltage of the air inlet valve closing drive output by the APU electronic controller is normal or not, and if the voltage is normal, a closing limit switch is switched on.

The invention has the following effective effects:

1. the method for controlling the air inlet valve of the auxiliary power device is simple to implement, and particularly can greatly improve the ignition success rate of the APU in the air state.

In an aerial state, an ECU (namely an APU electronic controller) can gradually open an inlet valve according to a preset functional relation f (Ma, N, P2) with flight Mach number, APU rotating speed and APU inlet pressure, so that the airflow entering the APU is relatively stable, the ignition is facilitated, the ignition success rate can be improved, particularly, the ignition success rate under the high-altitude high-Mach-number condition is also facilitated, and the APU is prevented from flameout. In conclusion, the auxiliary power device intake valve control method disclosed by the invention can realize the opening and closing control of the intake valve and can greatly improve the ignition success rate of the APU in the air state. The method can be applied to APU air intake control with wide flight bag width and complex use working conditions.

2. The full-open/full-close state of the inlet valve is identified, and the dual-redundancy design of the position sensor and the position switch is adopted, so that the task reliability of the system is improved; the opening/closing drive of the intake valve is cut off at the limit position, and the dual-redundancy design of ECU software cutting off and limit switch cutting off is adopted, so that the use safety of the product is improved.

Drawings

FIG. 1 is a schematic view of a portion of an auxiliary power unit intake valve control system.

FIG. 2 is a block diagram of an internal functional circuit of the ECU;

FIG. 3 is a block diagram of the internal functional circuitry of the intake valve actuating mechanism.

Detailed Description

The invention is described in further detail below with reference to the figures and the embodiments.

As shown in fig. 1, the intake valve control system of the auxiliary power unit of the present embodiment is composed of an APU electronic controller (abbreviated as ECU) and an intake valve actuating mechanism, and is used for controlling the opening and closing of the intake valve of the APU on the ground and in the air. And the ECU sends an opening or closing instruction of the intake valve according to the operation mode of the APU, the actuating mechanism completes operation according to the instruction, and feeds back the state and position information of the intake valve in real time, so that closed-loop control of the intake valve is completed. The control of the intake valve of the APU is an important point of the APU control, if the intake valve is not opened, the APU is started, if the intake valve is not opened, the starting is not successful, and if the intake valve is not opened, the APU is over-heated, surging and the like are caused, so that the APU is seriously damaged. The invention can accurately control the opening or closing of the APU inlet valve and can also control the opening degree of the APU inlet valve, thereby regulating the air input amount entering the APU combustion chamber and obviously improving the ignition success rate of the APU, and can be applied to the control of the APU inlet valve with wide flight envelope and complex use working conditions.

As can be seen from fig. 2, the ECU of the present embodiment mainly includes a CPU, a discrete quantity output interface circuit, an open drive circuit, a close drive circuit, a first open detection circuit, a first over-current detection circuit, a second open detection circuit, a second over-current detection circuit, a discrete quantity input interface circuit, a power supply output circuit, and a position signal decoding circuit; as can be seen from fig. 3, the intake valve actuating mechanism of the present embodiment mainly includes a motor, an actuating link mechanism, a position sensor, a fully-open position switch, an open limit switch, a fully-closed position switch, and a close limit switch.

The opening driving circuit and the closing driving circuit are respectively used for outputting an inlet valve opening driving and an inlet valve closing driving according to a control instruction output by the CPU; the first open-circuit detection circuit, the first overcurrent detection circuit, the second open-circuit detection circuit and the second overcurrent detection circuit are respectively used for detecting the motor state in the opening and closing processes of the inlet valve; the discrete quantity input interface circuit comprises a full-open position switch signal receiving end, an air inlet valve moving signal receiving end and a full-close position switch signal receiving end, and is respectively used for receiving a full-open position switch signal, an air inlet valve moving signal and a full-close position switch signal output by an air inlet valve actuating mechanism and sending the signals to the CPU; the power supply output circuit is used for outputting an intake valve indication power supply signal; the position signal decoding circuit is used for resolving an intake valve real-time position signal fed back by a position sensor in the intake valve actuating mechanism and sending the resolved intake valve real-time position signal to the CPU. The CPU outputs a control instruction by combining the resolved real-time position signal of the intake valve and the relevant signal fed back by the discrete quantity input interface circuit according to the starting instruction of the APU, and controls the real-time position of the intake valve to be consistent with the predetermined expected position; or outputting a control command by combining the stop command of the APU and the real-time position signal of the intake valve to control the intake valve to close.

A motor in the intake valve actuating mechanism is used for controlling the position of the intake valve through an actuating connecting rod mechanism according to instructions, and a position sensor is used for acquiring intake valve position signals and feeding back intake valve state and position information to an APU electronic controller in real time; the full-on position switch, the opening limit switch, the full-off position switch and the closing limit switch are all single-pole double-throw switches, and the full-on position switch and the opening limit switch are linkage switches; the fixed end of the full-open position switch is connected with a signal receiving end of the full-open position switch of the APU electronic controller, one side of the movable end is grounded, and the other side of the movable end is connected with an indication power supply signal of an inlet valve; the fixed end of the opening limit switch is connected with the output end of an opening drive circuit of an intake valve of an APU electronic controller, one side of the movable end is connected with a motor and a moving signal receiving end of the intake valve of the APU electronic controller, and the other side of the movable end is disconnected; the full-off position switch and the off limit switch are linked switches; the fixed end of the full-off position switch is connected with a signal receiving end of the full-off position switch of the APU electronic controller, one side of the movable end is grounded, and the other side of the movable end is connected with an indication power supply signal of an inlet valve; and the fixed end of the closing limit switch is connected with the output end of an air inlet valve closing drive circuit of the APU electronic controller, one side of the movable end is connected with the motor and an air inlet valve moving signal receiving end of the APU electronic controller, and the other side of the movable end is disconnected.

The dual-redundancy design of the position sensor and the position switch is adopted, so that the task reliability of the system is improved; the opening/closing drive of the intake valve is cut off at the limit position, and the dual-redundancy design of ECU software cutting off and limit switch cutting off is adopted, so that the use safety of the product is improved.

As can be seen from fig. 3, the intake valve actuating mechanism of the present embodiment further includes an MCU, a position signal feedback circuit, a driving detection circuit, an output signal conditioning circuit, and a fault signal output circuit; the position signal feedback circuit is used for conditioning the position signal of the intake valve acquired by the position sensor and sending the conditioned and converted position signal of the intake valve to a position signal decoding circuit in an APU electronic controller; the driving detection circuit is used for detecting whether the voltage of the intake valve opening driving or the intake valve closing driving output by the APU electronic controller is normal or not; and feeding back to the MCU; the MCU controls the actions of opening and closing the limit switch according to the feedback result; the output signal conditioning circuit is used for conditioning a full-open position switch signal, a full-close position switch signal and an inlet valve movement signal which are fed back to the APU electronic controller; and the fault signal output circuit is used for sending self fault information detected by the air inlet valve actuating mechanism to an APU electronic controller or other fault recording equipment.

The processing steps and related parameters included in this embodiment are as follows:

1. calculation of desired position of intake valve:

1.1, setting the maximum opening alpha of the inlet valve to be 60 degrees, and when the airplane is on the ground, setting the expected opening position of the inlet valve to be 60 degrees.

1.2, when the airplane is in the air, the expected opening position of the intake valve is a function relationship f (Ma, N, P2) of the flight Mach number Ma, the APU rotating speed N and the APU inlet pressure P2. The functional relationship is shown in tables 1 and 2:

TABLE 1 air P2>60kpa

TABLE 2 air P2<55kpa

2. Intake valve opening control:

and (3) controlling the opening of an inlet valve, and if the airplane is on the ground: the intake valve is opened directly to the fully open position 60 °;

the fully open state of the intake valve is recognized by the following conditions:

α₁the value of (A) is related to the installation position and the characteristics of the air inlet valve, and is less than 60 degrees and set as 57 degrees; t is t₂The minimum time required for the intake valve to move to full stroke should be < 24s, set to 8 s.

When any two conditions are satisfied, the intake valve is judged to be fully opened. a1, the position sensor works normally, and the opening of the air inlet valve is more than or equal to 57 degrees; b1, the fully-opened position switch works normally and indicates that the inlet valve is fully opened; c1, and the intake valve opening drive output is 8s or more.

If the aircraft is in the air, let us assume that the APU is started and the intake valve is opened under the conditions of 5km (P2 is about 50kpa) and Ma being 0.78 in the air, the embodiment is as follows:

2.1 in the scheme, in order to avoid damaging the ECU, the APU air inlet valve must be at the time t₁Moving the full stroke in the inner part, and according to engineering experience, dividing t₁Was designated as 24 s.

2.2, the ECU completes self-checking before starting and outputs the opening driving of the intake valve immediately after receiving an APU starting instruction.

2.3, the ECU can monitor whether the motor is in an overcurrent working process, when the motor is in the overcurrent state, the output of the opening drive of the inlet valve is stopped, and the waiting time t is_wAfter which an output intake valve opening drive is again attempted, t_wIf the flow is continuously overflowed for 4 times, the intake valve opening drive is not output any more.

2.4, the ECU outputs an inlet valve opening drive, the inlet valve actuating mechanism detects whether the voltage of the inlet valve opening drive output by the ECU is normal, if so, the opening limit switch is switched on to control a motor of the inlet valve actuating mechanism to rotate in the positive direction so as to drive an actuating connecting rod mechanism to actuate, finally, an aircraft inlet valve is driven to rotate to open, a position sensor acquires an inlet valve position signal, the inlet valve position signal is fed back to the ECU after conditioning, the inlet valve opening drive is cut off when the position sensor feeds back that the inlet valve reaches 10 degrees, and the position is kept; when N is more than 30%, the ECU outputs the opening drive of the air inlet valve again, and cuts off the opening drive of the air inlet valve when the position sensor feeds back that the air inlet valve reaches 20 degrees and keeps the position; when N is more than 50%, the ECU outputs the opening drive of the intake valve again, cuts off the opening drive of the intake valve when the position sensor feeds back that the intake valve reaches 40 degrees, and keeps the position; when N > 95%, the ECU outputs the intake valve opening drive again, and cuts off the intake valve opening drive when the position sensor feeds back that the intake valve reaches the full open position by 60 DEG, and maintains the position.

If position sensor trouble, then cut off the (air) intake valve and open the drive when full open position switch feedback full-open signal, simultaneously, full open position switch and open limit switch are the linked switch, and when full open position switch feedback full-open signal, open limit switch and will also cut off the (air) intake valve and open the drive, play the dual fail-safe effect, prevent that the stifled commentaries on classics from leading to the (air) intake valve damage. When the position sensor, the fully-open position switch and the open limit switch simultaneously have faults, fault information is sent to an APU electronic controller or other fault recording equipment, output and open driving are stopped, protective parking is carried out, and the APU is prohibited from starting. When the ECU outputs the opening drive of the intake valve for t1 time, if the intake valve does not reach the expected position, the output of the opening drive is stopped, protective stop is performed, and the APU is prohibited from starting.

3. Intake valve closing control:

3.1 in the scheme, in order to avoid damaging the ECU, the APU air inlet valve must be at the time t₁Moving the full stroke in the inner part, and according to engineering experience, dividing t₁Was designated as 24 s.

3.2, in order to ensure the operation safety of the APU, after the ECU receives the normal shutdown command of the APU, the cold drop of the APU is finished and the rotating speed is reduced to N_dThe intake valve closing drive is immediately output as follows. According to engineering experience, N is calculated_dThe setting is 7%, that is, when the APU rotation speed drops below 7% after the vehicle is stopped, the intake valve closing drive is immediately output.

3.3, the ECU can monitor whether the motor is in an overcurrent working process, when the motor is in the overcurrent state, the output of the closing drive of the inlet valve is stopped, and the waiting time t is_wAfter that, the output of the intake valve closing drive is tried again, t_wIf the flow rate is set to 6s, the intake valve closing drive is not output any more if the flow rate is continuously increased 4 times.

And 3.4, the ECU outputs an inlet valve closing drive, the inlet valve actuating mechanism detects whether the voltage of the inlet valve closing drive output by the APU electronic controller is normal, if so, the closing limit switch is switched on, the inlet valve actuating mechanism feeds real-time position information back to the ECU through the position sensor, and the drive is cut off until the position sensor feeds back that the inlet valve reaches a full-closed position.

The fully closed intake valve state is identified by the following conditions:

α₂the value of (A) is related to the installation position and the characteristics of the air inlet valve, and is more than 0 degree and is set to be 3 degrees; t is t₂Required for movement of inlet valve to full strokeThe shortest time should be < 24s, set to 8 s. When any two conditions are satisfied, the intake valve is judged to be fully opened. a2, the position sensor works normally, and the opening of the air inlet valve is less than or equal to 3 degrees; b2, the fully-closed position switch works normally and indicates that the inlet valve is fully closed; c2, and the intake valve opening drive output is 8s or more.

If the position sensor is in fault, the closing drive is cut off until the full-closing position switch feeds back a full-closing signal, meanwhile, the full-closing position switch and the closing limit switch are linked switches, and when the full-closing position switch feeds back the full-closing signal, the closing limit switch also cuts off the closing drive, so that a double-safety effect is achieved, and the damage of an inlet valve caused by locked rotor is prevented. When the position sensor, the fully-closed position switch and the closing limit switch simultaneously fail, failure information is sent to an APU electronic controller or other failure recording equipment, and the ECU cuts off the driving when the time t2 for the closing driving of the air inlet valve is output, wherein t2 is the shortest time required for the air inlet valve to move to the full stroke and should be less than t 1. When the ECU outputs the intake valve closing drive at time t1, the output of the closing drive is stopped if the intake valve has not reached the fully closed position.