UAV Engine Starting Method and System

Abstract

The application provides a UAV engine starting method and system, and the method comprises the following steps: collecting fuel information, rotating speed information and propeller torque information; starting the engine to drive the propeller to rotate, judging the oil pressure in the rotating speed information and the fuel information, when the rotating speed information and the oil pressure meet a first set range; detecting the pitch adjusting device according to the rotating speed information and the propeller torque information, when the pitch adjusting device meets a set condition, the engine starting is successful. The automatic detection of the pitch adjusting device of the UAV is realized, on the one hand, the detection efficiency is improved, and on the other hand, the accuracy and timeliness of the stability judgment of the UAV power system before starting the UAV each time are improved.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) engine control technology, and in particular to a UAV engine starting method and system. Background Technology

[0002] With the development of the aviation industry, the use of drones has become more and more frequent. When a drone takes off, the engine needs to undergo various status checks and warm-up.

[0003] A prior patent application with application number 2021112175384 discloses a method for starting a drone engine, including: acquiring an engine start command; acquiring an engine start signal fed back by the propulsion system, determining whether the engine start signal is permissible, and if so, controlling the electromechanical system to brake; otherwise, stopping the starting process; acquiring the brake pressure fed back by the electromechanical system, and after a first time interval, if the brake pressure is greater than the static brake specified pressure value, sending an idle throttle position command; otherwise, sending a stop throttle position command and stopping the starting process; after a second time interval, sending an engine start command to the propulsion system; acquiring the engine start status fed back by the propulsion system; determining the start result fed back by the propulsion system, and if a start success status signal is received within a third time interval, maintaining the current command status; if a start failure status signal is received, sending a stop throttle position command and stopping the starting process. The reference dimensions involved in this engine start method include the engine start signal, brake pressure, and the determination of the engine start status.

[0004] Another existing patent application with application number 2019108893144 discloses an automatic start-up method and system for unmanned aerial vehicles (UAVs), a storage medium, and electronic equipment. This automatic start-up method collects the UAV's fuel pressure value, fuel information, engine speed information, throttle position information, and choke position information; it then detects the fuel supply system based on the fuel pressure value, throttle position information, and choke position information; when the fuel supply system meets a first preset condition, it detects the ignition switch based on the fuel information and engine speed information; when the ignition switch meets a second preset condition, it detects the throttle servo based on the fuel information, engine speed information, and throttle position information; and when the throttle servo meets a third preset condition, it controls the UAV to start.

[0005] However, existing technologies lack detection methods for pitch control. Summary of the Invention

[0006] This invention provides a method and system for starting a drone engine, which solves the problem of the lack of a detection method for pitch control in the prior art.

[0007] This invention provides a method for starting a drone engine, wherein the drone includes a pitch adjustment device, and includes the following steps:

[0008] Step S110: Collect fuel information, speed information, and propeller torque information;

[0009] Step S120: Start the engine to drive the propeller to rotate, and judge the lubricating oil pressure in the speed information and fuel information. When the speed information and the lubricating oil pressure meet the first set range;

[0010] Step S130: The pitch adjustment device is detected based on the speed information and the propeller torque information. When the pitch adjustment device meets the set conditions, the engine starts successfully.

[0011] Furthermore, the detection of the pitch adjustment device based on the rotational speed information and the propeller torque information includes sequentially performing a first state detection, a second state detection, and a third state detection;

[0012] The first state detection includes: adjusting the pitch and propeller speed to a first cruise state, briefly adjusting the propeller speed to a first detection state, maintaining it for a first set time, and then releasing the adjustment of the propeller speed.

[0013] A first state detection is performed based on the propeller speed information. When the propeller speed information returns to the first cruise state, a second state detection is performed; otherwise, an anomaly is reported.

[0014] Furthermore, the second state detection includes: adjusting the pitch and propeller speed to a second cruise state, and adjusting the pitch to the second detection state via the pitch adjustment device;

[0015] A second state detection is performed based on the propeller's rotational speed and torque information. When the propeller's rotational speed and torque information meet a second set range, a third state detection is performed; otherwise, an anomaly is reported.

[0016] Furthermore, the third state detection includes: restoring the pitch to the position of the second cruise state using the pitch adjustment device;

[0017] The third state detection is performed based on the propeller speed and propeller torque information. When the propeller speed and propeller torque information return to the second cruise state, the third state detection is completed and the lubricating oil temperature is judged. Otherwise, an abnormality is reported. When the lubricating oil temperature meets the third set range, the pitch adjustment device is detected.

[0018] Furthermore, after any one of the first, second, or third state detections triggers an anomaly report, the following safety reset steps are performed:

[0019] Adjust the throttle lever to idle speed and maintain it for the second set time;

[0020] Adjust the pitch to the parking position pitch;

[0021] Turn off the ignition switch, generator control switch, and battery switch.

[0022] Further, before step S110, the sensor parameter information and onboard fuel balance information of the UAV are acquired. When the sensor parameter information and onboard fuel balance information meet the fourth set range, the fuel information, speed information and propeller torque information are collected; otherwise, an abnormal signal is reported and the start-up is terminated.

[0023] Furthermore, the starting engine driving the propeller rotation includes a starting motor driving stage and an engine driving stage executed sequentially, the starting motor driving stage including the following steps:

[0024] Step S121: Turn on the starter motor power supply, adjust the throttle lever to idle speed, and turn off unnecessary loads. The starter motor drives the engine to rotate.

[0025] Step S122: Determine the engine speed information. When the engine speed information is greater than the first preset threshold, proceed to the engine drive phase. The non-essential loads include one or more of the following: fuel valve, engine anti-icing, auxiliary fuel pump, and generator switch.

[0026] Furthermore, in step S122, after the engine speed information is greater than the first preset threshold and before the engine is driven, the engine cylinder head temperature in the fuel information is judged.

[0027] When the engine cylinder head temperature meets the fifth set range, directly turn on the engine ignition and connect the engine start switch.

[0028] Otherwise, open the choke first, then turn on the engine ignition and turn on the engine start switch.

[0029] Furthermore, the engine-driven phase includes the following steps:

[0030] Step S123: Adjust the pitch to the set position and open the fuel valve;

[0031] Step S124: Determine the exhaust temperature in the fuel information. When the exhaust temperature reaches the preset overload range, disconnect the engine start switch, close the fuel valve, and report an abnormality; when the exhaust temperature does not reach the preset overload range;

[0032] Step S125: Determine the lubricating oil pressure in the engine speed information and fuel information. If the lubricating oil pressure in the engine speed information and fuel information does not meet the sixth set range, disconnect the engine start switch, close the fuel valve, and report the abnormality; if the lubricating oil pressure in the engine speed information and fuel information meets the sixth set range.

[0033] Step S126: Determine the engine speed information. When the engine speed information meets the second preset threshold, disconnect the engine start switch, close the choke, and complete the starting of the engine to drive the propeller to rotate.

[0034] The present invention also provides an unmanned aerial vehicle (UAV) engine starting system, wherein the UAV includes a pitch adjustment device and further includes a data acquisition device for acquiring speed information, fuel information and propeller torque information;

[0035] A detection device is used to detect the pitch adjustment device based on the speed information and the propeller torque information when the lubricating oil pressure in the speed information and fuel information meets a first set range.

[0036] Engine start control device, used to start the engine to drive the propeller to rotate;

[0037] The controller is used to control the UAV to start when the pitch adjustment device meets the set conditions; the detection device and the engine start control device are integrated into the controller.

[0038] The beneficial effects provided by this invention are as follows:

[0039] By collecting fuel information, engine speed information, and propeller torque information, and driving the propeller to rotate via the starter motor and engine, the lubricating oil pressure in the engine speed and fuel information is judged. When the engine speed and the lubricating oil pressure meet a first set range, the pitch adjustment device is detected based on the engine speed and propeller torque information. When the pitch adjustment device meets the set conditions, the start-up is successful. This achieves automatic detection of the UAV pitch adjustment device, improving detection efficiency and the accuracy and timeliness of judging the stability of the UAV's power system before each UAV start-up. Attached Figure Description

[0040] Figure 1 This is a flowchart of the starting method of the present invention.

[0041] Figure 2 This is a schematic diagram illustrating the working principle of the starting method of this invention.

[0042] Figure 3 This is a structural block diagram of the starting system of the present invention.

[0043] Figure label:

[0044] 1. Controller; 2. Data acquisition device; 3. Throttle lever; 31. Pitch lever; 4. Choke control device; 5. Fuel valve; 6. Generator; 7. Anti-icing device; 8. Auxiliary fuel pump; 9. Engine start control device; 91. Engine ignition switch; 92. Engine start switch. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0046] The terms "first" and "second" in the specification and claims of this invention may explicitly or implicitly include one or more of those features. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0047] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0048] The following is combined with Figures 1-3 The present invention describes a method for starting an unmanned aerial vehicle (UAV) engine.

[0049] like Figure 1 As shown, this invention discloses a method for starting a drone engine, comprising the following steps:

[0050] Step S110: Collect fuel information, speed information, and propeller torque information;

[0051] Step S120: Start the engine to drive the propeller to rotate, and judge the lubricating oil pressure in the speed information and fuel information. When the speed information and lubricating oil pressure meet the first set range;

[0052] Step S130: The pitch adjustment device is tested based on the speed information and propeller torque information. When the pitch adjustment device meets the set conditions, the engine starts successfully.

[0053] Specifically, the UAV includes a power supply system, a fuel supply system, a starter motor, an engine, a choke adjustment device, and an ignition device. In step S110, the fuel information includes engine cylinder head temperature information, engine exhaust temperature information, lubricating oil pressure information, and lubricating oil temperature information. Cylinder head temperature information, engine exhaust temperature information, and lubricating oil temperature information are collected separately using temperature sensors; specifically, a K-type thermocouple sensor can be used as the temperature sensor. Lubricating oil pressure information is collected using a pressure sensor. Rotational speed information includes engine rotational speed information and propeller rotational speed information, which is collected using a rotational speed sensor. Specifically, the engine crankshaft rotational speed information and propeller rotational speed information can be collected in real time using a magnetoelectric rotational speed sensor.

[0054] The propeller is driven to rotate by a starter motor and an engine. Specifically, the starter motor shaft is connected to the engine shaft, and the engine shaft drives the propeller to rotate.

[0055] Specifically, in step S120, the engine speed information and lubricating oil pressure satisfying the first set range are defined as the engine speed reaching the detection speed range and the lubricating oil pressure meeting the preset test pressure range and being able to operate stably for a preset time. The method for judging the lubricating oil pressure in the engine speed information and fuel information includes the following steps:

[0056] Step S127: When the engine speed reaches the detection speed range;

[0057] Step S128: Determine the lubricating oil pressure. If the lubricating oil pressure does not meet the preset test pressure range, close the fuel valve and report an abnormality. If the lubricating oil pressure meets the preset test pressure range, wait for the engine to run for a preset time and then determine whether the engine status is normal.

[0058] A normal engine condition is defined as the engine speed remaining within the detection range and the lubricating oil pressure meeting the preset test pressure range. If the engine condition remains normal, proceed to the next step; otherwise, an error is reported.

[0059] In some embodiments, upon receiving an abnormality report, the throttle lever is adjusted to idle speed and maintained for a second set time, which is set to 2 minutes; the pitch is adjusted to the parking position pitch; and the ignition switch, generator control switch, and battery switch are turned off to ensure a safe power-off of the system.

[0060] Specifically, the detection speed range is set to 1980-2020 rpm, the preset test pressure range is set to greater than or equal to 2 bar, and the preset time is set to 1 minute. Of course, other values ​​can be used as the judgment criteria depending on the type of drone and the testing standards.

[0061] This application discloses a specific embodiment 1 to provide a detailed description of step S120.

[0062] Example 1, the method for determining the lubricating oil pressure in speed information and fuel information includes the following steps:

[0063] Step S127: When the engine speed reaches 1980-2020 rpm;

[0064] Step S128: Determine the lubricating oil pressure. When the lubricating oil pressure is less than 2 bar, close the fuel valve and report an abnormality. When the lubricating oil pressure is greater than or equal to 2 bar, determine whether the engine maintains a speed of 1980-2020 rpm and a lubricating oil pressure greater than or equal to 2 bar.

[0065] If so, then the engine status is determined to be normal and there are no warning signs.

[0066] If not, report an error and simultaneously adjust the throttle lever to idle and maintain it for the second set time, which is set to 2 minutes; adjust the pitch to the parking position pitch; turn off the ignition switch, generator control switch, and battery switch to ensure the system is safely powered off.

[0067] The pitch adjustment device is tested based on the speed and propeller torque information. When the pitch adjustment device meets the set conditions, the start-up is successful.

[0068] The system enables automatic detection of the drone's propeller pitch adjustment device, which improves detection efficiency and the accuracy and timeliness of the stability assessment of the drone's power system before each drone start-up.

[0069] Furthermore, in step S130, the pitch adjustment device is detected based on the rotational speed information and propeller torque information, including a first state detection, a second state detection, and a third state detection performed sequentially.

[0070] Specifically, the conditions set in step S130 are as follows:

[0071] In the first detection state, after the adjustment of the propeller speed is released, the propeller speed information can be restored to the first cruise state; in the second detection state, when the pitch adjustment device adjusts the pitch to the second detection state, the speed information and propeller torque information meet the second set range; in the third detection state, when the pitch adjustment device adjusts the pitch to restore the second cruise state, the propeller speed information and propeller torque information can be restored to the second cruise state.

[0072] The first state detection includes: adjusting the pitch and propeller speed to the first cruise state, briefly adjusting the propeller speed to the first detection state, maintaining it for a first set time, and then releasing the adjustment of the propeller speed.

[0073] The first state detection is performed based on the propeller speed information. That is, after the adjustment of the propeller speed is released, the propeller speed information returns to the first cruise state. When this condition is met, the second state detection is performed; otherwise, an anomaly is reported.

[0074] Specifically, the pitch adjustment device is set as a pitch lever. During the first state test, the propeller pitch and propeller speed are adjusted by the pitch lever and throttle lever respectively to adjust the pitch and propeller speed to the first cruise state. The propeller speed is then briefly adjusted to the first test state by the propeller overspeed test switch.

[0075] Specifically, the first cruise state is set as follows: the propeller speed is maintained at 1700-1750 rpm and the pitch lever is adjusted to the position of maximum propeller speed, at which point the corresponding pitch is the minimum. The propeller speed in the first detection state is set to 1625-1665 rpm, and the first set time is set to 0.1-0.3 seconds. Of course, other values ​​can be used as the judgment criteria depending on the type of drone and the detection standards.

[0076] This application discloses a specific embodiment 2 to provide a detailed description of the process of first state detection.

[0077] In Example 2, during the first state detection, the pitch is adjusted to the maximum speed position of the propeller by using the pitch lever, and the propeller speed is adjusted to 1725 rpm by using the throttle.

[0078] Press the propeller overspeed test switch and release it within 0.2 seconds to determine the propeller speed during this process;

[0079] When the propeller overspeed test switch is pressed, the propeller speed should decrease by 60-100 rpm; and after the propeller overspeed test switch is released, the propeller speed should recover to 1725±25 rpm before entering the second state detection. If either of the above two conditions is not met, an anomaly will be reported.

[0080] In some specific embodiments, while reporting the anomaly, the throttle lever is adjusted to idle speed and maintained for a second set time, which is set to 2 minutes; the pitch is adjusted to the parking position pitch; and the ignition switch, generator control switch, and battery switch are turned off to ensure safe power disconnection of the system.

[0081] Furthermore, the second state detection includes: adjusting the pitch and propeller speed to the second cruise state, and adjusting the pitch to the second detection state through the pitch adjustment device;

[0082] A second state detection is performed based on the propeller speed and torque information. When the propeller speed and torque information meet the second set range, a third state detection is performed; otherwise, an anomaly is reported.

[0083] Specifically, the second cruise state is set to a propeller speed of 2030 rpm and the pitch lever is adjusted to the maximum propeller speed position, at which point the corresponding pitch is at its minimum. The second detection state is set to the pitch lever being adjusted to the minimum propeller speed position, at which point the corresponding propeller pitch reaches its maximum position. The second setting range is set to a propeller speed decrease to 1605 rpm-1645 rpm, resulting in a 19%-21% increase in propeller torque.

[0084] This application discloses a specific embodiment 3 to provide a detailed description of the process of second state detection.

[0085] In Example 3, during the second state detection, the pitch lever is adjusted to the position of maximum propeller speed, and the propeller speed is adjusted to 2030 rpm by using the throttle lever;

[0086] Then, adjust the pitch lever to the position of minimum propeller speed and judge the propeller speed information and propeller torque information;

[0087] When the propeller speed drops to 1605rpm-1645rpm and the propeller torque increases by 19%-21% at the same time, the third state detection is performed.

[0088] If the propeller speed and propeller torque do not meet any of the above ranges, report an abnormality, adjust the throttle lever to idle speed and maintain it for the second set time, which is set to 2 minutes; adjust the pitch to the parking position pitch; turn off the ignition switch, generator control switch and battery switch to ensure the system is safely powered off.

[0089] Furthermore, the third state detection includes: restoring the pitch to the position of the second cruise state via the pitch adjustment device;

[0090] The third state detection is performed based on the propeller speed and propeller torque information. When the propeller speed and propeller torque information return to the second cruise state, the third state detection is completed and the lubricating oil temperature is judged. Otherwise, an abnormality is reported. When the lubricating oil temperature meets the third set range, the pitch adjustment device is detected.

[0091] This application discloses a specific embodiment 4 to provide a detailed description of the process of third state detection.

[0092] In Example 4, during the third state detection, the pitch is restored to the position of maximum propeller speed by using the pitch lever, and the propeller speed information and propeller torque information are judged.

[0093] When the propeller speed information recovers to 2030±50rpm, the lubricating oil temperature is judged;

[0094] Otherwise, report the anomaly, adjust the throttle lever to idle and maintain it for the second set time, which is set to 2 minutes; adjust the pitch to the parking position pitch; turn off the ignition switch, generator control switch and battery switch to ensure the system is safely powered off.

[0095] When judging the lubricating oil temperature, the third setting range is set to greater than 50℃. When the lubricating oil temperature is greater than 50℃, the pitch adjustment device is checked, the flight control is notified, and the engine starts successfully.

[0096] Otherwise, wait for the lubricating oil temperature to rise above 50°C before completing the pitch adjustment device test, reporting back to the flight control system, indicating a successful engine start. Determining the lubricating oil temperature helps identify the engine's operating status and reduces cold start wear.

[0097] In some alternative embodiments, engine parameters (such as oil temperature, oil pressure, and speed) are transmitted to the ground station in real time via the CAN bus. If an abnormality is detected (such as a 20% drop in lubricating oil pressure), a three-level alarm (beep, light, and SMS) is immediately triggered, which can extend the engine overhaul cycle and reduce the probability of sudden failures during flight through real-time status monitoring.

[0098] Further, before step S110, sensor parameter information and onboard fuel balance information of the UAV are acquired. When the sensor parameter information and onboard fuel balance information meet the fourth set range, fuel information, speed information and propeller torque information are collected. Otherwise, an abnormal signal is reported and the start-up is terminated.

[0099] Specifically, before collecting fuel information, engine speed information, and propeller torque information, a self-check is performed on the sensor parameters and onboard fuel level information. The sensor parameters include engine speed, propeller speed, cylinder head temperature, engine exhaust temperature, lubricating oil pressure, and lubricating oil temperature. All of these sensor parameters are collected by their respective sensors. The self-check method for sensor parameters includes a dual-sensor comparison method. This involves setting up two sensors at the same data collection location and comparing the data from the two sensors that return the same information. If the deviation exceeds 5%, a fault warning is triggered; otherwise, the sensor parameters at that location are considered normal.

[0100] For example, regarding engine speed information, two speed sensors are set up to simultaneously pre-collect engine speed information, and the data of the engine speed signals collected by the two speed sensors are compared. If the deviation exceeds 5%, a fault warning is triggered; if the deviation is less than or equal to 5%, the speed sensor parameters at the engine are reported as normal. This avoids starting failures caused by sensor malfunctions (such as signal drift) or insufficient fuel, reducing the probability of sensor misjudgment from 3% in traditional solutions to below 0.1%.

[0101] The method for self-checking the onboard fuel level information uses an ultrasonic level sensor to measure the fuel tank level and a pressure sensor to monitor the fuel line pressure. When the fuel tank level is lower than a set threshold, the system determines that the onboard fuel level is below the starting threshold, automatically prevents starting, and prompts the user to refuel.

[0102] Specifically, before formally collecting fuel information, speed information, and propeller torque information in step S110, the sensor parameter information at various locations is pre-collected, and the pre-collected sensor parameter information is tested. When the sensor parameter information and onboard fuel balance information meet the fourth preset range, it is set as follows: when the sensor parameter deviation is less than 5% and the fuel balance is higher than the 20L starting threshold. That is, when the sensor parameter deviation is less than 5% and the fuel balance is higher than the 20L starting threshold, the UAV's self-test is considered passed, and it is allowed to proceed to step S110; otherwise, an anomaly is reported.

[0103] In another alternative embodiment, a triple sensor redundancy architecture can be adopted, for example, by combining dual speed sensors with an independent oil temperature sensor and using a cyclic redundancy check (CRC) algorithm to verify the integrity of sensor data in real time, thereby achieving multi-dimensional verification of the sensors and oil quantity.

[0104] Furthermore, starting the engine to drive the propeller to rotate includes a starter motor drive stage and an engine drive stage executed sequentially. The starter motor drive stage includes the following steps:

[0105] Step S121: Turn on the starter motor power supply, adjust the throttle lever to idle speed, and turn off unnecessary loads. The starter motor drives the engine to rotate.

[0106] Step S122: Determine the engine speed information. When the engine speed information is greater than the first preset threshold, proceed to the engine drive phase. The non-essential loads include one or more of the following: fuel valve, engine anti-icing, auxiliary fuel pump, and generator switch.

[0107] Specifically, the engine-driven propeller rotation is configured to execute a starter motor drive phase and an engine drive phase sequentially. In the starter motor drive phase, the starter motor power supply is first turned on, the throttle lever is adjusted to idle speed, and the throttle valve is closed, so only the starter motor drives the engine shaft to rotate. At the same time, when the starter motor power supply is turned on, unnecessary loads are shut off.

[0108] By implementing an auxiliary isolation strategy for the power system, the control unit disconnects unnecessary loads on the engine-side power generation load (such as the generator excitation circuit) and the aircraft-side starting bus (such as standby power for avionics) via relays (SSRs) before startup, controlling bus voltage fluctuations within ±2%. This eliminates the voltage drop caused by electrical load interference during traditional startup (reducing the drop from 15% to 3%), increasing the startup success rate in low-temperature environments from 60% to over 95%. Specifically, unnecessary loads also include engine anti-icing, auxiliary fuel pumps, and generator switches.

[0109] In step S122, the engine speed information is judged. When the engine speed information is greater than a first preset threshold, the engine driving phase is initiated. Specifically, the first preset threshold is set to 1200 rpm. Of course, other values ​​can be used as the judgment criteria depending on the type of UAV and the detection standards.

[0110] Furthermore, in step S122, after the engine speed information is greater than the first preset threshold and before the engine is driven, the engine cylinder head temperature in the fuel information is judged.

[0111] When the engine cylinder head temperature meets the fifth set range, directly turn on the engine ignition and connect the engine start switch 92;

[0112] Otherwise, open the choke first, then turn on the engine ignition and turn on the engine start switch 92;

[0113] Specifically, the engine cylinder head temperature is determined after the engine speed exceeds a first preset threshold and before the engine is driven.

[0114] Specifically, the fifth preset range for engine cylinder head temperature is set to an engine cylinder head temperature greater than 50°C. When the engine cylinder head temperature is greater than 50°C, the engine ignition is directly turned on and the engine start switch 92 is activated. When the engine cylinder head temperature is less than or equal to 50°C, the choke is opened in advance before turning on the engine ignition and activating the engine start switch 92. The opening of the choke is adjusted by the rudder-controlled choke device. Traditional starting methods require manual judgment of choke opening based on engine stability, resulting in a "one-size-fits-all" phenomenon that leads to cold start stalling. Opening the choke in advance when the engine cylinder head temperature is less than or equal to 50°C increases the air-fuel mixture concentration when entering the engine drive phase, thus avoiding the cold start stalling problem caused by the "one-size-fits-all" phenomenon.

[0115] In some alternative embodiments, a platinum resistance temperature sensor can be used to update the engine cylinder head temperature data every 0.5 seconds, and the choke opening can be dynamically adjusted through a PID algorithm to improve control accuracy.

[0116] This application discloses a specific embodiment 5 to provide a detailed description of the starter motor drive stage.

[0117] Example 5, the starting motor drive stage includes the following steps:

[0118] Step S121: Turn on the starter motor power supply, adjust the throttle lever to idle speed, and disconnect the engine-side generator load, aircraft-side starter bus load, engine anti-icing, auxiliary fuel pump and generator switch via relay at the control end;

[0119] Step S122: Determine the engine speed information. When the engine speed information is greater than 1200 rpm, determine the engine cylinder head temperature in the fuel information. When the engine cylinder head temperature is greater than 50℃, directly turn on the engine ignition and connect the engine start switch 92.

[0120] When the engine cylinder head temperature is less than or equal to 50°C, open the choke in advance, then turn on the engine ignition and turn on the engine start switch 92. Adjust the opening of the choke through the rudder-controlled choke device.

[0121] Then, the engine-driven phase begins.

[0122] Furthermore, the engine-driven phase includes the following steps:

[0123] Step S123: Adjust the pitch to the set position and open the fuel valve;

[0124] Step S124: Determine the exhaust temperature in the fuel information. When the exhaust temperature reaches the preset overload range, disconnect the engine start switch 92, close the fuel valve, and report an abnormality; when the exhaust temperature does not reach the preset overload range;

[0125] Step S125: Determine the lubricating oil pressure in the engine speed information and fuel information; when the lubricating oil pressure in the engine speed information and fuel information does not meet the sixth set range, disconnect the engine start switch 92, close the fuel valve, and report the abnormality; when the lubricating oil pressure in the engine speed information and fuel information meets the sixth set range.

[0126] Step S126: Determine the engine speed information. When the engine speed information meets the second preset threshold, disconnect the engine start switch 92, close the choke, and complete the engine start to drive the propeller to rotate.

[0127] Specifically, in step S123, the set position is set to the position when the pitch lever is moved to the position of maximum propeller speed. The fuel valve is opened, at which point the engine ignition and engine start switch 92 are already turned on, so combustion should have started in the cylinder.

[0128] In step S124, the preset overload range is set as follows: exhaust temperature greater than 810℃ or exhaust temperature greater than 738℃ for more than 5 minutes. When either condition is met, the engine start switch 92 is disconnected, the fuel valve is closed, and an abnormality report is triggered. This reduces the risk of mechanical damage during the starting process and avoids accidents such as engine cylinder scoring and knocking caused by untimely feedback of abnormal parameters in traditional solutions. Of course, other values ​​can be used as the judgment criteria depending on the type of drone and the testing standards.

[0129] In step S125, the sixth setting range is set such that when the engine speed reaches 1500 rpm, the propeller speed is positive (the propeller thrust on the UAV is the same as the UAV's cruise direction) and the lubricating oil pressure is positive. Specifically, for monitoring the lubricating oil pressure, the main oil passage pressure is monitored by a piezoresistive pressure sensor, and the engine speed is monitored to determine whether to release the engine start switch 92.

[0130] In step S126, the engine speed information of the second preset threshold is set to 1800 rpm. When the engine speed information reaches 1800 rpm, it is determined that the engine speed information meets the second preset threshold.

[0131] In Example 5, the crankshaft speed information of the engine is collected in real time by a magnetoelectric speed sensor, and a safe lower limit threshold for crankshaft speed is set. If the crankshaft speed is lower than the safe lower limit threshold for more than 2 seconds during the start-up process, secondary ignition is triggered.

[0132] In Example 5, a K-type thermocouple sensor is used to collect exhaust temperature information, and a first safety threshold and a second safety threshold for exhaust temperature are set. When the collected exhaust temperature information is higher than the first safety threshold, the fuel injection quantity is automatically reduced by controlling the fuel valve. When the collected exhaust temperature information is higher than the second safety threshold, the fuel valve and engine start switch 92 are automatically activated to shut off the engine and prevent overheating damage to the turbocharger.

[0133] This application discloses a specific embodiment 6 to provide a detailed description of the engine drive phase.

[0134] Example 6, the engine-driven phase includes the following steps:

[0135] Step S123: Move the pitch lever to the position where the propeller speed is at its maximum, and open the fuel valve;

[0136] Step S124: Determine the exhaust temperature in the fuel information;

[0137] If the exhaust temperature exceeds 810℃ or 738℃ for more than 5 minutes, disconnect the engine start switch 92, close the fuel valve, and report the abnormality.

[0138] When the exhaust temperature is less than 738℃ or the exhaust temperature is between 738-810℃ but the duration is less than 5 minutes, the engine speed information and the lubricating oil pressure in the fuel information are judged.

[0139] Step S125: Control the engine speed to increase by controlling the throttle lever and monitor it in real time. When the engine speed reaches 1500 rpm, judge the propeller speed and lubricating oil pressure. The propeller forward speed is defined as the propeller thrust on the UAV is the same as the UAV's cruise direction.

[0140] When the propeller speed is not in the positive direction or the lubricating oil pressure is not positive, disconnect the engine start switch 92, close the fuel valve, and report the abnormality.

[0141] When the propeller speed is positive and the lubricating oil pressure is positive, the engine speed information is judged;

[0142] Step S126: When the engine speed reaches 1800 rpm, disconnect the engine start switch 92, close the choke, and start the engine to drive the propeller to rotate; otherwise, wait for the engine speed to reach 1800 rpm before disconnecting the engine start switch 92 and closing the choke.

[0143] To enable those skilled in the art to better understand the technical solution of this application, the implementation process of the entire UAV engine starting method of this application will be described in detail below with reference to specific embodiment 7.

[0144] Example 7, as Figure 2 As shown, the drone includes a propeller stick, and the drone engine starting method includes the following steps:

[0145] Step S108: Determine if any of the engine sensors are abnormal. If they are abnormal, proceed to the ground troubleshooting process and exit the starting procedure.

[0146] Step S109: Determine if the onboard fuel level is greater than 20L. If it is, turn on the starting power supply; otherwise, report an abnormal fuel level and exit the starting process.

[0147] Step S110: Collect fuel information, speed information, and propeller torque information;

[0148] Fuel information includes engine cylinder head temperature, engine exhaust temperature, lubricating oil pressure, and lubricating oil temperature; speed information includes engine speed and propeller speed.

[0149] Step S121: Turn on the power supply system to supply power to the starter motor and adjust the throttle lever to idle speed.

[0150] Close the fuel valve to ensure dry-start operation and prevent fuel flooding of the cylinder;

[0151] Turn off engine anti-icing and reduce the load on the power supply bus;

[0152] Turn off the auxiliary fuel pump to reduce the load on the power supply bus.

[0153] Turn off the generator switch to reduce the torque load during engine startup.

[0154] The starter motor drives the engine to rotate.

[0155] The engine cylinder head temperature in the fuel information is judged. When the engine cylinder head temperature is greater than 50°C, the engine ignition can be turned on directly and the engine start switch 92 can be turned on. Otherwise, the choke needs to be opened to help start the engine, and then the engine ignition can be turned on and the engine start switch 92 can be turned on.

[0156] When the engine ignition is turned on, power is supplied to the ignition coils inside the engine cylinders.

[0157] The engine start switch 92 is open, but because the fuel valve is closed, there is no oil in the cylinder, and the starter motor drives the engine shaft to rotate.

[0158] Step S122: Determine the engine speed information;

[0159] When the engine speed is greater than 1200 rpm, proceed to the next step.

[0160] Step S123: Move the pitch lever to the position where the propeller speed is at its maximum, and open the fuel valve;

[0161] Step S124: Determine the exhaust temperature in the fuel information;

[0162] If the exhaust temperature exceeds 810℃ or 738℃ for more than 5 minutes, disconnect the engine start switch 92, close the fuel valve, and report the abnormality.

[0163] When the exhaust temperature is less than 738℃ or the exhaust temperature is between 738-810℃ but lasts for less than 5 minutes, the engine speed information and the lubricating oil pressure in the fuel information are judged; the engine speed is controlled to increase by controlling the throttle lever and monitored in real time; when the engine speed information reaches 1500rpm;

[0164] Step S125: Determine the propeller speed and lubricating oil pressure information. The propeller forward speed is defined as the propeller thrust on the UAV being in the same direction as the UAV's cruise direction.

[0165] When the propeller speed is not in the forward direction or the lubricating oil pressure is not positive, disconnect the engine start switch 92, close the fuel valve, and report the abnormality; when the propeller speed is in the forward direction and the lubricating oil pressure is positive;

[0166] Step S126: Determine the engine speed information. When the engine speed information reaches 1800 rpm, disconnect the engine start switch 92, close the choke, and complete the engine start to drive the propeller to rotate, and the engine will work normally; otherwise, wait for the engine speed information to reach 1800 rpm before disconnecting the engine start switch 92 and closing the choke.

[0167] Then, the engine speed information and the lubricating oil pressure in the fuel information are judged, specifically including the following steps:

[0168] Step S127: When the engine speed reaches 2000 rpm;

[0169] Step S128: Determine the lubricating oil pressure. When the lubricating oil pressure is less than 2 bar, close the fuel valve and report an abnormality. When the lubricating oil pressure is greater than or equal to 2 bar, wait for the engine to run for 1 minute.

[0170] Determine if the engine speed is maintained within the range of 1980-2020 rpm and the lubricating oil pressure is maintained at or above 2 bar. If so, proceed to the next step. Otherwise, report an abnormality, adjust the throttle lever to idle speed and maintain it for 2 minutes; adjust the pitch to the parking position; turn off the ignition switch, generator control switch, and battery switch.

[0171] Step S130: Perform first state detection, second state detection and third state detection on the pitch adjustment device in sequence according to the rotation speed information and the propeller torque information;

[0172] The first state detection includes the following steps:

[0173] Step S1301: Adjust the pitch lever to the position of maximum propeller speed, adjust the throttle lever to the position of maximum propeller speed, and press the propeller overspeed test switch. Release the propeller overspeed test switch at 0.2.

[0174] Step S1302: Determine the propeller speed information during this process; when the propeller overspeed test switch is pressed, the propeller speed information should decrease by 60-100 rpm and the propeller speed should recover to 1725±25 rpm after the propeller overspeed test switch is released, then enter the second state detection.

[0175] Otherwise, report an anomaly, and simultaneously adjust the throttle lever to idle speed and maintain it for 2 minutes; adjust the pitch to the parking position pitch; turn off the ignition switch, generator control switch, and battery switch.

[0176] The second state detection includes the following steps:

[0177] Step S1303: Adjust the pitch lever to the maximum propeller speed position, and adjust the propeller speed to 2030 rpm using the throttle lever; adjust the pitch lever to the minimum propeller speed position.

[0178] Step S1304: Determine the propeller speed and propeller torque information; when the propeller speed drops to 1605rpm-1645rpm and the propeller torque increases by 19%-21% at the same time, perform the third state detection.

[0179] Otherwise, report an anomaly and adjust the throttle lever to idle and maintain it for the second set time, which is set to 2 minutes; adjust the pitch to the parking position pitch; turn off the ignition switch, generator control switch, and battery switch.

[0180] The third state detection includes the following steps:

[0181] Step S1305: Restore the pitch to the position of maximum propeller speed using the pitch lever;

[0182] Step S1306: Determine the propeller speed and propeller torque information;

[0183] When the propeller speed information recovers to 2030±50rpm, the lubricating oil temperature is checked; otherwise, an abnormality is reported, and the throttle lever is adjusted to idle speed and maintained for the second set time, which is set to 2 minutes. The pitch is adjusted to the parking position pitch. The ignition switch, generator control switch, and battery switch are turned off to ensure the system is safely powered off.

[0184] Step S1307: When judging the lubricating oil temperature, if the lubricating oil temperature is greater than 50°C, the pitch adjustment device is checked, the flight controller is notified, and the engine starts successfully. Otherwise, wait for the lubricating oil temperature to rise above 50°C before checking the pitch adjustment device, the flight controller is notified, and the engine starts successfully. The automatic engine start-up process ends.

[0185] This invention also discloses a drone engine starting system, such as... Figure 3 As shown, the UAV includes a pitch adjustment device and a data acquisition device 2, which is used to collect speed information, fuel information and propeller torque information.

[0186] A detection device is used to detect the pitch adjustment device based on the speed information and the propeller torque information when the lubricating oil pressure in the speed information and fuel information meets a first set range.

[0187] Engine start control device 9 is used to execute step S120 to start the engine and drive the propeller to rotate.

[0188] The controller 1 is used to control the UAV to start when the pitch adjustment device meets the set conditions; the detection device and the engine start control device 9 are integrated into the controller 1.

[0189] Specifically, the UAV (not shown in the diagram) includes a fuel tank, fuel valve 5, auxiliary fuel pump 8, engine anti-icing device 7, drive unit, generator 6, throttle lever 3, propeller lever 31, choke control device 4, engine ignition switch 91, and engine start switch 92. The drive unit includes an engine, a starter motor for starting the engine, and a propeller driven by the engine. Multiple drive units can be provided. The choke control device 4 can be a rudder-controlled choke device used to control the choke opening.

[0190] Data acquisition device 2 includes:

[0191] Speed ​​sensors (not shown in the diagram) are used to collect engine speed and propeller speed information respectively; temperature sensors (not shown in the diagram) are used to collect cylinder head temperature, engine exhaust temperature, and lubricating oil temperature information respectively; pressure sensors are used to collect lubricating oil pressure information, and level sensors are used to collect oil tank level information (not shown in the diagram). Multiple sensors can be set at each location where information needs to be collected, facilitating the testing of deviation values ​​of information collected by multiple sensors. For example, if two speed sensors are connected to the engine simultaneously to collect engine speed information, the engine speed information collected by the two speed sensors is compared. If the deviation is greater than a set deviation threshold, the speed sensor connected to the engine is considered damaged.

[0192] The controller 1 is used to control the UAV to start when the pitch adjustment device meets the set conditions; the propeller overspeed test switch is integrated into the detection device, and the detection device and the engine start control device 9 are integrated into the controller 1.

[0193] The data acquisition device 2, fuel valve 5, generator 6, throttle lever 3, pitch lever 31, choke control device 4, and engine ignition switch 91 are respectively connected to controller 1.

[0194] The controller 1 controls the adjustment of the throttle lever 3, the pitch lever 31, and the choke control device 4. The controller 1 may integrate relays, which control the opening and closing of the fuel valve 5, the generator 6, the anti-icing device 7, the auxiliary fuel pump 8, the engine ignition switch 91, and the engine start switch 92.

[0195] Furthermore, a self-testing device is also included, integrated into the controller 1, which controls the acquisition device 2 to acquire fuel information, speed information, and propeller torque information when the sensor parameter information and onboard fuel balance information meet the fourth preset range. Where there is no conflict, the above embodiments and features described herein can be combined with each other.

[0196] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for starting an engine of an unmanned aerial vehicle, said unmanned aerial vehicle comprising a pitch adjustment device, characterized in that, The method comprises the following steps: Step S110: collecting fuel information, rotation speed information and propeller torque information; Step S120: starting the engine to drive the propeller to rotate, and judging the rotation speed information and the fuel information, when the rotation speed information and the fuel information meet a first set range; Step S130: detecting the pitch adjusting device according to the rotation speed information and the propeller torque information, when the pitch adjusting device meets a set condition, the engine starting is successful.

2. The method of claim 1, wherein, The detecting the pitch adjusting device according to the rotation speed information and the propeller torque information comprises first state detection, second state detection and third state detection executed in sequence; The first state detection comprises: adjusting the pitch and the propeller rotation speed to a first cruising state, controlling the propeller rotation speed to be adjusted to a first detection state for a short time, and releasing the adjustment of the propeller rotation speed after maintaining for a first set time; The first state detection is performed according to the rotation speed information of the propeller, when the rotation speed information of the propeller returns to the first cruising state, the second state detection is performed, otherwise an abnormality is reported.

3. The method of claim 2, wherein, The second state detection comprises: adjusting the pitch and the propeller rotation speed to a second cruising state, and adjusting the pitch to a second detection state by the pitch adjusting device; The second state detection is performed according to the rotation speed information and the propeller torque information of the propeller, when the rotation speed information and the propeller torque information of the propeller meet a second set range, the third state detection is performed, otherwise an abnormality is reported.

4. The method of claim 3, wherein, The third state detection comprises: restoring the pitch to a position of the second cruising state by the pitch adjusting device; The third state detection is performed according to the rotation speed information and the propeller torque information of the propeller, when the rotation speed information and the propeller torque information of the propeller return to the second cruising state, the third state detection is completed and the oil temperature is judged; otherwise an abnormality is reported, when the oil temperature meets a third set range, the detection of the pitch adjusting device is completed.

5. The method of claim 4, wherein, After any state detection in the first state detection, the second state detection or the third state detection triggers an abnormality report, the following safety reset steps are executed: Adjusting the throttle lever to an idle speed and maintaining for a second set time; Adjusting the pitch to a parking position pitch; Turning off the ignition switch, the generator control switch and the battery switch.

6. The UAV engine starting method of claim 1, wherein Before the step S110, sensor parameter information and on-board fuel remaining information of the unmanned aerial vehicle are acquired, when the sensor parameter information and the on-board fuel remaining information meet a fourth set range, the fuel information, the rotation speed information and the propeller torque information are collected; Otherwise, an abnormality signal is reported and the starting is terminated.

7. The method of claim 1, wherein: The starting the engine to drive the propeller to rotate comprises a starting motor driving stage and an engine driving stage executed in sequence, the starting motor driving stage comprises the following steps: Step S121: turning on starting motor power supply, adjusting the throttle lever to an idle speed state, turning off unnecessary loads, and starting the motor to drive the engine to rotate; Step S122: judging the speed information of the engine, when the speed information of the engine is greater than the first preset threshold, the engine driving stage is carried out, and the unnecessary load includes one or more of the fuel valve, the engine anti-icing, the auxiliary fuel pump and the generator switch.

8. The method of claim 7, wherein: In the step S122, after the speed information of the engine is greater than the first preset threshold, the engine head temperature in the fuel information is judged before the engine driving is carried out. When the engine head temperature meets the fifth set range, the engine ignition is directly turned on and the engine starting switch is turned on. Otherwise, the choke valve is opened first, then the engine ignition is turned on and the engine starting switch is turned on.

9. The method of claim 7, wherein, The engine driving stage includes the following steps: Step S123: adjusting the pitch to the set position and opening the fuel valve; Step S124: judging the exhaust temperature in the fuel information, when the exhaust temperature reaches the preset overload range, the engine starting switch is turned off, the fuel valve is closed and the abnormality is reported; when the exhaust temperature does not reach the preset overload range; Step S125: judging the speed information of the engine and the oil pressure in the fuel information, when the speed information of the engine and the oil pressure in the fuel information do not meet the sixth set range, the engine starting switch is turned off, the fuel valve is closed and the abnormality is reported; when the speed information of the engine and the oil pressure in the fuel information meet the sixth set range; Step S126: judging the speed information of the engine, when the speed information of the engine meets the second preset threshold, the engine starting switch is turned off, the choke valve is closed and the starting engine driving propeller rotation is completed.

10. A UAV engine starting system, said UAV comprising a pitch adjustment device, characterized in that, Further comprising: The acquisition device is used for collecting the speed information, the fuel information and the propeller torque information; The detection device is used for detecting the pitch adjusting device according to the speed information and the propeller torque information when the speed information and the oil pressure in the fuel information meet the first set range; The engine starting control device is used for starting the engine driving propeller rotation; The controller is used for controlling the unmanned aerial vehicle to complete the starting when the pitch adjusting device meets the set condition; the detection device and the engine starting control device are integrated in the controller.

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