Garden machine galloping flameout protection method and system, intelligent terminal and storage medium

Abstract

The invention relates to the technical field of engine control methods, in particular to a garden machine galloping flameout protection method and system, an intelligent terminal and a storage medium, and the method comprises the steps that the current rotating speed of an engine is monitored in real time; the current rotating speed is compared with a preset flameout protection threshold value, and the flameout protection threshold value is set to be higher than the highest set working rotating speed which can be maintained by the engine electronic speed regulating system in the normal working state; when the current rotating speed exceeds the flameout protection threshold value, it is judged that the engine enters a rotating speed out-of-control state, and an emergency protection instruction is generated immediately; and executing the emergency protection instruction, controlling the engine to execute flameout operation, and triggering an instrument to output overspeed alarm information. The overspeed protection method has the effect of improving the problems that an existing overspeed protection method is delayed in response and weak in rotating speed relevance.

Description

Technical Field

[0001] This application relates to the technical field of engine control methods, and in particular to a method, system, intelligent terminal, and storage medium for protecting garden machinery from engine failure. Background Technology

[0002] In the field of garden machinery, equipment such as lawnmowers and brush cutters powered by gasoline engines are widely used. These devices typically use mechanical or electronic speed control systems to regulate the engine throttle opening, thereby maintaining the equipment's operation within a set speed range. During use, mechanical connecting components of the speed control system, such as cables, springs, and levers, may malfunction due to fatigue, wear, jamming, or accidental detachment. When such a malfunction occurs, the engine loses its speed feedback and regulation capabilities, and the throttle remains fully open or at a large opening position, causing the engine speed to rise rapidly and uncontrollably, commonly known as runaway. Runaway generates enormous instantaneous loads, leading to damage to internal engine parts such as connecting rods and pistons, and even causing serious safety accidents such as engine disintegration, posing a threat to operators and the surrounding environment.

[0003] In related technologies, a common protection measure is to integrate a mechanical overspeed protection device into the engine block. When the engine speed exceeds a set mechanical threshold, the protection device directly cuts off the ignition or fuel supply through physical linkage. Another measure is to install an oil pressure or level sensor in the lubrication system. When insufficient oil pressure is detected, the engine is forced to shut down, indirectly preventing abnormal engine speed caused by poor lubrication.

[0004] Regarding the aforementioned technologies, mechanical overspeed protection devices are typically complex in structure and expensive, and their activation thresholds are fixed at the factory, making it impossible to interact and coordinate with the vehicle's electronic control system. Their response thresholds are generally set high, usually only triggering when the engine speed is extremely abnormal. They are slow to react or fail to trigger when the engine speed rises within a dangerous range but does not reach an extremely high value, resulting in a protection blind spot. Oil pressure-based protection measures have a weak direct correlation between the protection logic and engine speed, and cannot respond immediately to overspeed conditions caused by speed control system failure. Summary of the Invention

[0005] To improve upon the problems of slow response and weak correlation with rotational speed in existing overspeed protection methods, this application provides a method, system, intelligent terminal, and storage medium for preventing runaway engine shutdown in garden machinery.

[0006] Firstly, this application provides a method for preventing runaway engine shutdown in garden machinery, employing the following technical solution: A method for preventing runaway engine shutdown in garden machinery, comprising: Real-time monitoring of the engine's current speed; The current speed is compared with the preset shutdown protection threshold, which is set to be higher than the highest set operating speed that the engine electronic speed control system can maintain under normal operating conditions. When the current engine speed exceeds the engine shutdown protection threshold, it is determined that the engine has entered a speed control failure state and an emergency protection command is immediately generated. The emergency protection command is executed, the engine is shut down, and the instrument panel outputs an overspeed alarm message.

[0007] By employing the above technical solution, the engine speed is continuously monitored and compared in real time with a fixed safety threshold that is clearly higher than the normal operating limit. Once the speed exceeds this threshold, the system instantly determines that the engine has entered a dangerous "runaway" state and immediately triggers protective commands including emergency shutdown and alarms. This overcomes the limitations of traditional mechanical overspeed protection devices, which rely on complex physical structures, have slow response times, and have unadjustable thresholds. It achieves rapid and accurate identification and intervention based on electrical signals, detects sharp increases in speed caused by speed control system failure, and actively cuts off power before the engine's mechanical load reaches a destructive critical point. This reduces the risk of internal component damage or even disintegration caused by engine overspeed, providing immediate and reliable active safety protection for operators and equipment.

[0008] Optionally, the method further includes an early warning and composite judgment step: When the current speed exceeds a preset warning threshold, a warning signal is generated, wherein the warning threshold is set to be higher than the maximum set operating speed and lower than the flameout protection threshold; Based on the warning signal, obtain the average rate of increase of the current rotational speed per unit time since the warning signal was generated; When the current engine speed exceeds the shutdown protection threshold and the average rate of increase exceeds the preset acceleration threshold, the engine is determined to have entered a speed runaway state.

[0009] By adopting the above technical solution, a direct and efficient electronic overspeed protection core logic was constructed. This method continuously monitors the engine's core operating parameter—speed—and compares it in real time with a fixed safety threshold that is clearly higher than the normal operating limit. Once the speed exceeds this threshold, the system instantly determines that the engine has entered a dangerous "runaway" state and immediately triggers protection commands including emergency shutdown and alarms. This solution fundamentally changes the limitations of traditional mechanical overspeed protection devices, which rely on complex physical structures, have slow response times, and have unadjustable thresholds, achieving rapid and accurate identification and intervention based on electrical signals. It can effectively detect a sharp increase in speed caused by speed control system failure and actively cut off power before the engine's mechanical load reaches a destructive critical point, thereby significantly reducing the major safety risk of internal component damage or even disintegration caused by engine overspeed operation, providing immediate and reliable active safety protection for operators and equipment.

[0010] Optionally, the steps following real-time monitoring of the engine's current speed may also include: The auxiliary signals characterizing the mechanical operating status of the engine are acquired in real time, wherein the auxiliary signals include at least one of vibration signals, oil pressure signals, and intake pressure signals; After the auxiliary verification step, it is determined whether the current speed exceeds the shutdown protection threshold and whether the auxiliary signal exceeds its corresponding normal operating range. If the current engine speed exceeds the shutdown protection threshold and the auxiliary signal exceeds its normal operating range, the engine is determined to have entered a speed control failure state.

[0011] By adopting the above technical solution and introducing a fusion mechanism of early warning and dual criteria, the accuracy of the system's identification of runaway conditions is improved. An early warning threshold, positioned between the normal operating speed and the emergency shutdown threshold, is established to detect abnormal speed trends early. The system does not immediately take final action upon reaching the warning threshold; instead, it simultaneously initiates analysis of the acceleration of the speed increase. Only when the speed not only exceeds a higher shutdown protection threshold but also exhibits abnormally rapid acceleration (i.e., the average rate of increase exceeds the preset acceleration threshold) is runaway confirmed. Through a composite judgment logic of exceeding limits and excessive acceleration, the system effectively distinguishes between speed fluctuations caused by normal short-term load changes and genuine runaway acceleration, reducing the probability of false shutdowns due to momentary interference or normal rapid acceleration, ensuring a safety baseline, and improving the smoothness of equipment operation.

[0012] Optionally, the steps for real-time monitoring of the engine's current speed include: The controller's timer unit captures the periodic pulse signal output by the engine speed sensor; The time interval Δt between the rising edges of consecutive pulses is calculated using the periodic measurement method. Calculate the instantaneous speed value N based on the preset pulse-speed conversion coefficient K. inst =K / Δt; Digital filtering is performed on m consecutively acquired instantaneous speed values ​​to obtain the current speed N for subsequent comparisons. The digital filtering process includes, but is not limited to, moving average filtering or median filtering, where m is calculated based on a preset filtering time window T. f It is calculated based on the instantaneous rotational speed sampling period.

[0013] By employing the above technical solution, a timer is used to capture speed pulses, and the time interval is calculated using a periodic measurement method. This time interval is then converted into instantaneous speed based on a calibration coefficient. The method's principle is clear, and the calculation is direct, providing high-precision raw data for subsequent judgment. The solution's step of digitally filtering the raw instantaneous speed signal, through continuous sampling of multiple points and the use of algorithms such as moving average or median filtering, effectively smooths out instantaneous jitter and noise in the speed signal caused by ignition pulses, transmission system backlash, or electromagnetic interference. The size of the filtering window is determined in relation to the physical time window, ensuring that the filtering effect can adapt to different engine speed ranges. This results in a highly stable and representative current speed value used for threshold comparison, avoiding potential protection logic misjudgments caused by speed value jumps due to signal noise, and improving the robustness and reliability of the entire protection system.

[0014] Optionally, the engine shutdown protection threshold and / or warning threshold are adaptive thresholds that are dynamically adjusted based on the real-time operating status of the engine. The dynamic adjustment methods include: At least one engine load characterization parameter is acquired in real time, including intake manifold absolute pressure, power output shaft load current, or hydraulic system pressure. Based on the real-time values ​​of the load characterization parameters, the dynamic basic safety threshold N is calculated through a predetermined mapping relationship. set ; Set the flameout protection threshold to N. set ; Set the warning threshold to λ·N set , where λ is a preset scaling factor, 0 < λ < 1.

[0015] By adopting the above technical solution, parameters that directly reflect the actual working load of the engine, such as intake pressure and load current, are collected in real time, and the basic value N of the safe speed threshold is dynamically calculated. setA fixed proportional coefficient λ is used to derive a logically related warning threshold and a shutdown protection threshold, one high and one low. This allows the protection threshold to automatically adjust according to different operating conditions, such as no-load, normal operation, and heavy-load uphill climbing. Under high-load conditions, the engine experiences greater mechanical stress, resulting in higher risk at the same speed. The system calculates and lowers the protection threshold accordingly, enabling early warning and intervention. Under light-load conditions, a higher threshold is restored or used to avoid unnecessary protection triggering. This adaptive mechanism makes the protection system more rational, ensuring safety under extreme conditions while improving operational smoothness under normal conditions.

[0016] Optionally, a dynamic basic security threshold N can be calculated using a predetermined mapping relationship. set The steps include: The baseline value L of the preset load characterization parameter base and its corresponding baseline security threshold N base ; The current basic safety threshold N is calculated using a linear compensation model. set； , where L current The load characterization parameter value is obtained in real time, and k is the load-speed sensitivity coefficient preset according to the engine model.

[0017] By adopting the above technical solution, the mapping relationship is concretized into a linear compensation mathematical model, and a baseline load L is preset. base and its corresponding reference safe speed N base This forms the reference origin for threshold adjustment. By introducing a load-speed sensitivity coefficient k, a linear relationship is established between load change and safe speed adjustment. When the real-time load L... current When the speed exceeds the reference speed, the current permissible safety threshold N is dynamically reduced by subtracting the value from the reference safe speed based on the product of the excess magnitude and the coefficient k. set The linear compensation model has a clear physical meaning, and its parameters can be obtained through engine bench tests and actual operation calibration, making it easy to implement and optimize in engineering. This enables the dynamic threshold adjustment function to have an algorithmic core, achieving self-adaptation, ensuring the continuity and predictability of the adjustment process, and avoiding threshold jumps.

[0018] Optionally, the steps following the engine shutdown operation may also include: A circular buffer is created in the non-volatile memory to continuously record the engine's operating data. The operating data entries include at least timestamps, engine speed, target throttle opening and actual throttle opening, and intake pressure. When it is determined that the engine has entered a speed control failure state and an emergency protection command is generated, the complete data segment within the first time period T1 before the trigger time and the second time period T2 after the trigger time is locked and saved. Based on the saved data segments, the system automatically generates a fault analysis report by analyzing the time sequence relationship between the speed and the actual throttle opening. The report identifies at least one possible root cause, which may include a stuck speed controller, a detached mechanical linkage component, or a distorted speed sensor signal.

[0019] By employing the above technical solution, utilizing non-volatile memory and a ring buffer technology, continuous background recording of engine operating data is achieved. In the event of speed loss and triggering an emergency shutdown, a complete data snapshot of the critical time periods before and after the event is automatically locked and saved, acting as a black box. Based on this data, the system analyzes the relationship and synergy between key parameters such as engine speed and actual throttle opening over time, automatically inferring and generating targeted fault analysis reports, clearly identifying potential root causes such as "speed regulator actuator jamming" or "mechanical linkage detachment." This solves the problem of traditional protection devices only processing data without analysis, providing a basis for tracing the cause of accidents.

[0020] Secondly, this application provides a method and system for preventing runaway engine shutdown in garden machinery, which adopts the following technical solution: A method and system for preventing runaway engine shutdown in garden machinery, including The acquisition module is used to acquire the engine's current speed, warning signals, auxiliary signals, and load characterization parameters. The auxiliary signals include at least one of vibration signals, oil pressure signals, and intake pressure signals. The load characterization parameters include at least one of intake manifold absolute pressure, power output shaft load current, or hydraulic system pressure. A memory for storing a program for a method of protecting garden machinery from runaway engine failure, as described above. The processor and memory programs can be loaded and executed by the processor to implement any of the above-mentioned methods for preventing runaway engine shutdown in garden machinery.

[0021] Thirdly, this application provides a smart terminal, which adopts the following technical solution: A smart terminal includes a memory and a processor, wherein the memory stores a computer program that can be loaded by the processor and executed as in any of the methods described above.

[0022] Fourthly, this application provides a computer storage medium capable of storing corresponding programs, employing the following technical solution: A computer-readable storage medium storing a computer program that can be loaded by a processor and executed any of the above-described methods for protecting garden machinery from engine failure.

[0023] In summary, this application includes at least one of the following beneficial technical effects: This application enables the system to continuously monitor engine speed throughout the entire operating phase and quickly compare it with a preset safety threshold, allowing for immediate identification and proactive intervention in the early stages of engine speed runaway. The system shifts from physical triggering to electrical signal decision-making, achieving millisecond-level rapid response. Before the engine's mechanical load reaches the critical point of failure, it proactively executes engine shutdown and alarm, preventing safety accidents from occurring. This application employs a dual-threshold early warning protection mechanism, combined with analysis of acceleration during engine speed rise, to effectively distinguish between normal load fluctuations and genuine uncontrolled rapid acceleration, thereby reducing the probability of false triggering. It integrates auxiliary signals reflecting the engine's mechanical state, such as vibration, oil pressure, and intake pressure, for cross-validation, forming redundant safety criteria based on multi-sensor information collaboration. Through a composite judgment logic combining over-limit and excessive acceleration with abnormal auxiliary signals, the confidence and robustness of system decisions are enhanced, avoiding false actions caused by a single sensor failure or signal interference, and ensuring the accuracy of protection commands. This application dynamically collects load parameters such as intake pressure and operating current, and uses a linear compensation model to adjust safety thresholds in real time and adaptively. This allows protection standards to intelligently change with the equipment's operating conditions, such as no-load and heavy-load, optimizing equipment availability while ensuring safety. The solution integrates black-box-style fault data recording and automatic source tracing analysis functions. After protection is triggered, it automatically saves complete data segments before and after the event. Based on the temporal logic between the data, it analyzes and reports suspected fault root causes, providing data evidence for subsequent accident analysis. Attached Figure Description

[0024] Figure 1 This is a flowchart of a method for protecting garden machinery from engine stall during overdrive, according to an embodiment of this application.

[0025] Figure 2 This is a flowchart of the warning and composite judgment steps in the embodiments of this application.

[0026] Figure 3 This is a flowchart of the steps following real-time monitoring of the engine's current speed in the embodiments of this application.

[0027] Figure 4 This is a flowchart of the steps for real-time monitoring of the engine's current speed in an embodiment of this application.

[0028] Figure 5 This is a flowchart of the dynamic adjustment method for adaptive thresholds in the embodiments of this application.

[0029] Figure 6 In this embodiment of the application, a dynamic basic security threshold N is calculated through a predetermined mapping relationship. set The flowchart of the steps.

[0030] Figure 7This is a flowchart of the steps after controlling the engine to perform a shutdown operation in the embodiments of this application.

[0031] Figure 8 This is a block diagram of a method system for preventing runaway engine shutdown of garden machinery, as described in an embodiment of this application. Detailed Implementation

[0032] The present application will be further described in detail below with reference to the accompanying drawings.

[0033] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the appendices in the embodiments of this application will be described below. Figure 1-8 The technical solutions in the embodiments of this application are clearly and completely described. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0035] This application discloses a method for preventing runaway engine shutdown in garden machinery. (Refer to...) Figure 1 Methods for preventing engine failure in garden machinery include: Step S100: Monitor the current engine speed in real time.

[0036] Real-time monitoring refers to continuously acquiring physical signals reflecting the instantaneous rotational speed of the engine at a rate no less than the main cycle frequency of the control system, and converting them into digital information that can be used for logic processing. The current engine speed refers to a numerical value representing the engine's rotational speed at the current or most recent moment, after necessary processing.

[0037] The monitoring function is performed by the engine control unit (ECU) of the garden machinery. The ECU is connected to the engine's speed sensor via a hardware input interface. The sensor (either magnetoelectric or Hall effect) converts the rotational motion of the engine crankshaft or flywheel into a regular electrical signal. The signal conditioning circuit and analog-to-digital converter module inside the ECU are responsible for converting the raw electrical signal into a digital quantity that the ECU can recognize. Then, by running the internally programmed signal reading program, this digital quantity is acquired at a fixed sampling period and used as the raw data characterizing the engine speed.

[0038] Step S101: Compare the current speed with the preset shutdown protection threshold, wherein the shutdown protection threshold is set to be higher than the highest set operating speed that the engine electronic speed control system can maintain under normal operating conditions.

[0039] The preset engine shutdown protection threshold is a fixed or calibrable value that is determined and stored before the system is started, and is used as a safety boundary to determine whether the engine speed has increased abnormally. The maximum set operating speed is the highest engine speed that the engine is allowed to reach and can maintain stably when the speed control function is normal, and is set by the engine electronic speed control system or the user.

[0040] The engine shutdown protection threshold is pre-written into the ECU's non-volatile memory. The method for determining the shutdown protection threshold value based on engine calibration data is as follows: The highest set operating speed (e.g., 3600 rpm) of the engine model under normal electronic speed control is obtained through experiments or technical specifications. To ensure safety redundancy and avoid false triggering at the edge of normal speed fluctuations, a relative safety increment (e.g., set to 4000 rpm) needs to be added to this baseline value to obtain the final shutdown protection threshold. In the ECU's main control loop, a comparison function is called to compare the real-time speed value obtained in step S100 with the shutdown protection threshold read from memory, outputting a Boolean value (true / false) to indicate whether the current speed exceeds the safety threshold.

[0041] Step S102: When the current speed exceeds the engine shutdown protection threshold, it is determined that the engine has entered a speed control failure state, and an emergency protection command is immediately generated.

[0042] Engine speed runaway refers to a fault mode in which the engine speed increases spontaneously and uncontrollably due to a failure in the speed control system. The emergency protection command is a logic signal generated internally by the ECU to initiate the highest priority safety response.

[0043] When the comparison function in step S101 continuously outputs "true" for a preset debouncing time (e.g., 100 milliseconds), the ECU's fault diagnosis and safety management module makes a logical judgment based on this. The module sets an internal fault flag representing "speed runaway". The setting of this flag is associated with a high-priority interrupt service routine (ISR). Once this routine is entered, the system generates an emergency protection command containing specific opcodes and parameters according to a preset strategy.

[0044] Step S102 is used to provide basic judgment logic. When the system further performs the following warning and compound judgment (steps S200-S202) or auxiliary signal verification (steps S300-S302), the corresponding compound judgment logic will be used as the final criterion, with higher priority than the basic judgment logic.

[0045] Step S103: Execute the emergency protection command, control the engine to perform a shutdown operation, and trigger the instrument to output an overspeed alarm message.

[0046] Performing an engine shutdown operation means that the ECU drives an external actuator to physically interrupt the engine's combustion process, forcing the engine to stop running. Triggering an overspeed warning message on the instrument panel means that the ECU sends a specific message to the driver information display unit through the vehicle communication network, generating a visual and / or audible warning.

[0047] The implementation involves two parallel execution paths: performing an engine shutdown operation and triggering an alarm message.

[0048] Executing an engine shutdown operation: The ECU's driver software reads the "emergency shutdown" command from the safety command queue and controls the corresponding power output interface according to the vehicle's electrical architecture and engine type. For example, for a system that shuts off the engine by cutting off the fuel supply, the ECU controls the output port of the fuel pump relay or fuel cut-off solenoid valve to de-energize; for a system that shuts off the engine by interrupting ignition, the ECU controls the power supply port of the ignition coil or the ignition signal output port to fail.

[0049] Triggering the alarm message: The ECU's communication protocol stack constructs a diagnostic message conforming to the vehicle network specifications. The message contains a diagnostic fault code identifying "engine overspeed" and a possible snapshot of instantaneous data. The ECU broadcasts the message to the vehicle bus via the communication ECU. Upon receiving the message, the instrument cluster or information display connected to the bus activates a specific warning icon (a flashing engine-shaped warning light) and displays warning text according to a pre-programmed display strategy. This process may be accompanied by an audible alert.

[0050] Reference Figure 2 The method further includes an early warning and composite judgment step: Step S200: When the current speed exceeds a preset warning threshold, a warning signal is generated, wherein the warning threshold is set to be higher than the maximum set operating speed and lower than the flameout protection threshold.

[0051] The warning threshold is a pre-set secondary safety speed limit used to provide early warning of abnormal speed trends. Its value lies between the engine's maximum set operating speed (normal upper limit) and the engine shutdown protection threshold (dangerous upper limit). The warning signal is a logic signal generated internally by the system, used to initiate more refined monitoring and preparatory responses when the speed reaches the warning threshold but not the danger threshold.

[0052] The warning threshold is an independent calibration parameter, stored together with the engine shutdown protection threshold in the ECU's non-volatile memory. It is typically set based on a fixed ratio or a fixed difference between the maximum set operating speed and the engine shutdown protection threshold. For example, if the maximum set operating speed is 3600 rpm and the engine shutdown protection threshold is 4200 rpm, then the warning threshold can be set to 3900 rpm.

[0053] When the ECU performs the numerical comparison in step S101, it compares the current engine speed N with the warning threshold in parallel. The comparison includes delay debouncing logic (if necessary, it must last for more than 50 milliseconds). Once the condition is met, a separate monitoring module within the ECU generates a warning signal. This is manifested by setting a specific status flag and possibly initiating a dedicated timing and data buffering task for calculating the rate of change of engine speed.

[0054] Step S201: Based on the warning signal, obtain the average rate of increase of the current rotational speed per unit time since the warning signal was generated.

[0055] The average rate of increase refers to the average rate of increase (e.g., revolutions per minute per second) of the engine's current speed within a specific unit of time starting from the moment the warning signal is generated. It is used to quantify the severity of the speed increase and is a key indicator for distinguishing between normal acceleration and runaway acceleration.

[0056] After the warning signal is generated, a dedicated data recording and analysis routine is activated. The routine performs the following operations: 1. Timestamp recording: Records the precise time T when the warning signal was generated. warn 2. Data buffer: from T warn 1. Starting from a certain time, the latest current rotational speed N is continuously stored in a circular buffer at a fixed sampling period (e.g., 20 milliseconds); 2. Rate calculation: After reaching the preset calculation window duration (e.g., 0.5 seconds), the starting time (T) is extracted from the buffer. warn ) and end time (T) warn The corresponding rotational speed N (+0.5 seconds) start and N end 4. Calculate the average rate of increase: Average rate of increase = (N end -N start ) / Calculation window duration, the result is in the unit of rotational speed change rate (e.g., revolutions per minute per second). For example, the warning signal in T warn The rotational speed N is generated and recorded at specific times. start The speed was 3850 revolutions per minute. After 0.5 seconds, the recorded rotational speed N was... end Given a speed of 4100 revolutions per minute, the average rate of ascent is calculated as a = (4100 - 3850) / 0.5 = 500 revolutions per minute per second.

[0057] Step S202: When the current speed exceeds the engine shutdown protection threshold and the average rate of increase exceeds the preset acceleration threshold, it is determined that the engine has entered a speed runaway state.

[0058] The acceleration threshold is a preset speed increase rate threshold value used to determine whether the speed increase is abnormal / out of control.

[0059] The judgment logic requires that both conditions be met simultaneously: "absolute speed value exceeds limit" (exceeding the engine shutdown protection threshold) and "abnormal speed change trend" (exceeding the acceleration threshold) before finally confirming "speed runaway state".

[0060] At this point, the ECU's fault determination logic integrates inputs from two sources: 1. The "over-shutdown protection threshold" signal from step S101, after debouncing processing; 2. The real-time average rate of rise calculated in step S201 and its comparison with a preset acceleration threshold. The acceleration threshold is also stored as a calibration parameter. The final determination function is called, performing a logical "AND" operation: IF(speed over-shutdown protection threshold == TRUE) AND (average rate of rise > acceleration threshold) THEN, indicating a speed runaway state.

[0061] The system will only set the highest-level fault flag of "speed runaway" and generate an emergency protection command (proceeding to steps S102 / S103) when both of the above conditions are met simultaneously. If only the speed exceeds the limit but the rate of increase is gradual, it may indicate other fault modes (such as sudden load shedding), and the system will adopt a different strategy (such as only alarming, without forced shutdown).

[0062] Reference Figure 3 The steps following real-time monitoring of the engine's current speed also include: Step S300: Acquire auxiliary signals characterizing the mechanical operating state of the engine in real time, wherein the auxiliary signals include at least one of vibration signals, oil pressure signals, and intake pressure signals.

[0063] Auxiliary signals characterizing the mechanical operating state of an engine refer to physical quantity signals, other than engine speed, that can directly or indirectly reflect the engine's internal mechanical load, operating health, and external load environment. These signals are used to cross-verify whether the engine is in abnormal operating conditions from different dimensions. Vibration signals mainly reflect the impact balance of moving parts inside the engine (such as pistons, connecting rods, and crankshafts) and the overall mechanical tightness of the engine; oil pressure signals reflect the working efficiency of the lubrication system, and abnormal pressure may indicate a surge in mechanical load due to insufficient lubrication; intake pressure signals usually refer to the absolute pressure of the intake manifold, reflecting the engine's intake load.

[0064] Auxiliary signals are acquired through various sensors installed on the engine or engine block, and collected by the corresponding analog or digital input channels of the ECU: 1. Vibration signals: The raw vibration waveform is acquired by an accelerometer (such as a piezoelectric or MEMS accelerometer) installed on the engine block or bracket. The ECU's built-in signal conditioning circuit amplifies and filters the waveform, samples it through an analog-to-digital converter (ADC), and further calculates the effective value (RMS) or the energy of a specific frequency band as a characteristic value. 2. Oil pressure signals: Acquired by an oil pressure sensor (piezoresistive type) installed on the engine's main oil passage. The sensor outputs a voltage or current signal proportional to the oil pressure, which is sampled by the ECU's ADC channel and converted into a pressure value. 3. Intake pressure signals: Acquired by an intake manifold pressure sensor (MAP sensor). The sensor outputs a voltage signal proportional to the absolute pressure in the manifold, which is sampled by the ECU's ADC channel and converted into a pressure value.

[0065] The ECU reads these auxiliary signals in parallel at a fixed sampling period, synchronized with or slightly delayed by the speed sampling, and stores them in an internal register or buffer for use by subsequent decision logic. For example, within one control cycle, the ECU simultaneously performs the following: reads the vibration acceleration value from ADC channel 1 and calculates its effective value (Vib) for the most recent 100 milliseconds. RMS =5.2m / s²; Read the oil pressure sensor voltage value from ADC channel 2 and convert it to Oil P =280kPa; Read the intake pressure sensor voltage value from ADC channel 3 and convert it to MAP=95kPa.

[0066] Step S301: After the auxiliary verification step, determine whether the current speed exceeds the shutdown protection threshold and whether the auxiliary signal exceeds its corresponding normal operating range.

[0067] The auxiliary verification step refers to the signal acquisition and preprocessing process in step S300, which involves parallel and independent dual-path judgment: the first judgment is based on the "primary criterion" of engine speed (whether the engine stall protection threshold is exceeded); the second judgment is based on the "auxiliary criterion" of the auxiliary signal (whether it exceeds its normal operating range). The normal operating range is a preset numerical interval for each auxiliary signal, within which the engine's mechanical operating state is considered to be basically normal.

[0068] The ECU's internal decision logic contains two independent comparators or decision functions: 1. Speed ​​determination, which can be multiplexed with or run independently and in parallel with step S101, outputting a Boolean value RPM. Over1. Indicate whether the current engine speed N has continuously exceeded the shutdown protection threshold; 2. Auxiliary signal judgment: For each auxiliary signal that needs to be verified (such as vibration and oil pressure selected) obtained in step S300, the ECU will determine its real-time value (such as Vib). RMS Oil P The signal is compared with the preset upper and lower limits of the normal operating range for that signal. The normal operating range is calibrated according to the engine model and operating conditions. For example, the normal operating range for oil pressure may be calibrated as [200, 450] kPa. A true comparison result (Aux) Abnormal =TRUE), if and only if at least one monitored auxiliary signal exceeds its normal operating range. These two checks are performed in parallel, and the output (RPM) Over and Aux Abnormal () is used as the input for step S302.

[0069] For example: System setting: Flare-off protection threshold RPM Protect =4200; Normal range of effective vibration value [0, 4.0] m / s²; Normal range of oil pressure [200, 450] kPa. Current status: N=4300 (continuously exceeding limits), Vib RMS =5.2m / s² (exceeding the upper limit), Oil P =280kPa (normal). Therefore, the judgment result is: RPM Over =TRUE,Aux Abnormal =TRUE (due to vibration exceeding limits).

[0070] In step S302, when the current engine speed exceeds the shutdown protection threshold and the auxiliary signal exceeds its normal operating range, it is determined that the engine has entered a speed runaway state.

[0071] The ECU's safety decision module receives two Boolean inputs, RPM, from step S301. Over and Aux Abnormal The module performs logical operations: Final Fault =RPM OverANDAux _ Abnorma l. Only when Final Fault When the calculation result is true, the system performs the same subsequent actions as in step S102, namely, setting the highest-level "speed runaway" fault flag and triggering the emergency protection process. If only the speed exceeds the limit while all auxiliary signals are normal, the system can determine it as another non-emergency fault (such as slight governor misalignment) and adopt a strategy of alarming but not forcibly shutting down the engine; if the auxiliary signals are abnormal but the speed is normal, it indicates a mechanical fault and similarly adopts different levels of alarms.

[0072] Reference Figure 4 The steps for real-time monitoring of the engine's current speed include: In step S400, the periodic pulse signal output by the engine speed sensor is captured by the timer unit of the controller.

[0073] A periodic pulse signal refers to a square wave or square wave-like electrical signal whose frequency is strictly proportional to the engine speed. It is generated by a speed sensor, and each pulse cycle corresponds to a fixed angle of rotation of the engine crankshaft. Capture refers to the controller (ECU) being able to accurately detect the moment when the edge (such as the rising edge) of the pulse signal occurs.

[0074] This is implemented by the ECU's hardware timer / counter module in input capture mode. The output signal from the speed sensor (such as a magnetoelectric sensor) is converted to a level suitable for digital logic by a signal conditioning circuit before being connected to a specific input capture pin of the timer module. The timer module can be configured to automatically record the current timer / counter value into a dedicated capture / compare register and generate an interrupt request when a preset valid edge (such as a rising edge) is detected on the input pin.

[0075] Step S401: Calculate the time interval Δt between the rising edges of consecutive pulses using the period measurement method.

[0076] The period measurement method indirectly calculates the signal frequency or period by measuring the time difference between two adjacent events of the same nature (in this case, the rising edge of a pulse). The time interval Δt is the length of time between two consecutive rising edges of a pulse, and its reciprocal is proportional to the pulse frequency, and thus proportional to the engine speed.

[0077] In the capture interrupt service routine or related task in step S400, the software reads the time value T from the current capture register. current And read the time value T saved during the last capture. last The time interval Δt is obtained by calculating the difference between two time points: Δt = T current -T last The difference is in the timer count cycle, which needs to be multiplied by the timer's count cycle time (obtained by dividing the system clock, such as 1 microsecond / count) to convert it to a physical time unit (such as microsecond). To handle the case of timer counter overflow (return to zero), overflow compensation is required during calculation.

[0078] Step S402: Calculate the instantaneous speed value N based on the preset pulse-speed conversion coefficient K. inst =K / Δt.

[0079] The pulse-to-speed conversion factor K is a constant that converts the time interval Δt into engine speed (in revolutions per minute, r / min). Physically, it represents the product of the number of pulses generated by the speed sensor (related to the number of flywheel teeth, etc.) and the time unit conversion factor within one engine revolution.

[0080] The coefficient K is pre-stored as a calibration parameter in non-volatile memory, and the calculation formula is K=(60·1,000,000) / PPR (when Δt is in microseconds). PPR (PulsePerRevolution) is the number of pulses generated by the sensor per revolution of the engine, determined by mechanical characteristics such as the number of flywheel teeth. After obtaining Δt (in microseconds) in step S401, a division operation is performed: N inst =K / Δt, the calculated result is N inst This refers to the instantaneous rotational speed in r / min.

[0081] Step S403: Perform digital filtering on the m consecutively acquired instantaneous speed values ​​to obtain the current speed N for subsequent comparison. The digital filtering process includes, but is not limited to, moving average filtering or median filtering, where m is calculated according to a preset filtering time window T. f It is calculated based on the instantaneous rotational speed sampling period.

[0082] Digital filtering is a process that uses software algorithms to process noisy sampled data and extract signals that better reflect the true trend. Moving average filtering takes the arithmetic mean of data within a certain window as the output; median filtering takes the median of data within that window as the output. The filtering time window Tf is the length of data time considered by the filter. The current rotational speed N is the smoothed rotational speed value used for subsequent safety logic such as threshold comparison.

[0083] The system maintains a circular buffer of length m in memory to store N obtained from the most recent m calculations. inst The value of m is determined by the desired filtering effect, where m = Tf / Ts, Ts is the sampling period of the instantaneous rotational speed (the execution period of steps S400-S402), and Tf is the preset filtering time window (e.g., 100 milliseconds). Each time a new N is calculated... inst It needs to be stored in the buffer and the oldest data should be overwritten.

[0084] If a moving average filter is used, then calculate all m N values ​​in the buffer. inst The arithmetic mean of the values ​​is used as the current N; if median filtering is used, the m N values ​​in the buffer are... inst The values ​​are sorted by size, and the value at the middle position is taken as the current N. The filtered N value is output and used for subsequent comparisons and judgments in steps S101 and beyond.

[0085] Reference Figure 5 The engine shutdown protection threshold and / or warning threshold are adaptive thresholds that are dynamically adjusted based on the real-time operating status of the engine. The dynamic adjustment methods include: Step S500: Acquire at least one engine load characterization parameter in real time. The load characterization parameter includes intake manifold absolute pressure, power output shaft load current, or hydraulic system pressure.

[0086] Engine load characterization parameters are physical quantities that directly and in real-time reflect the engine's current output power or the external resistance it is experiencing. Intake manifold absolute pressure (MAP) is directly related to the engine's intake air volume, reflecting the load; power take-off shaft load current reflects the electrical power required to drive working components (such as the cutter head and hydraulic pump), characterizing the mechanical load; hydraulic system pressure reflects the working resistance of hydraulic actuators (such as lifting cylinders). These parameters allow us to determine whether the engine is under light, normal, or heavy load.

[0087] The acquisition of each load characterization parameter relies on the corresponding sensor, which is sampled by the analog input channel (ADC) of the controller (ECU). The intake manifold absolute pressure is obtained through an intake manifold pressure sensor (MAP sensor). The sensor outputs a voltage signal, which the ECU converts into a pressure value (in kPa) according to a calibrated conversion relationship. The power take-off shaft load current is obtained by connecting a Hall current sensor in series in the power supply circuit of the drive motor on the power take-off shaft (PTO) or by using a shunt. The ECU samples this signal and converts it into a current value (in A). The hydraulic system pressure is obtained by acquiring an oil pressure signal from a pressure sensor installed on the main hydraulic line. The ECU samples this signal and converts it into a pressure value (in MPa or psi). The ECU reads the latest value of the parameter at a fixed control cycle (e.g., 100ms).

[0088] Step S501: Calculate the dynamic basic safety threshold N based on the real-time values ​​of the load characterization parameters through a predetermined mapping relationship. set .

[0089] A predetermined mapping relationship is a rule, function, or data table describing the correspondence between load characterization parameters and the maximum permissible safe speed. The dynamic basic safety threshold N set It refers to the original safe speed threshold baseline value calculated based on the current real-time load, without scaling.

[0090] The mapping relationship is pre-stored in the ECU's non-volatile memory in the form of data or algorithms. Implementation methods include table lookup or linear formula methods. 1. Table Lookup: A two-dimensional lookup table is established, with the horizontal axis representing the load parameter (e.g., MAP value) and the vertical axis representing the corresponding N... set The ECU obtains N based on real-time load parameters by looking up a table (interpolation calculations may be required). set2. Linear formula method: using a linear compensation model, Among them, N base For the reference load L base The base safe speed, k is the load influence coefficient, in RPM / (load unit), L current This represents the real-time load value. N base L base Both k and k are preset calibration constants. After obtaining the real-time load value, the ECU calls the corresponding mapping function or lookup table program to calculate the current dynamic basic safety threshold N. set .

[0091] Step S502: Set the flameout protection threshold to N. set .

[0092] The dynamic basic safety threshold N calculated in step S501 is used as the basis for calculation. set The value is directly assigned to the "shutdown protection threshold" used for the final emergency shutdown judgment, and the maximum safe speed that the engine can reach will change dynamically according to the load.

[0093] The ECU calculates N in step S501. set Then, it is immediately updated in the internal variable or register used to store the "flameout protection threshold". This variable is used to replace the previously existing fixed threshold and takes effect in the next control cycle, used in the comparison logic in step S101.

[0094] Step S503: Set the warning threshold to λ·N set , where λ is a preset scaling factor, 0 < λ < 1.

[0095] Dynamic flameout protection threshold N set Based on this, a lower "early warning threshold" is derived by multiplying by a fixed proportional coefficient λ less than 1, ensuring that the early warning threshold is always lower than the flameout protection threshold, and the two maintain a fixed proportional relationship, which is dynamically adjusted together with the load.

[0096] The proportional gain λ is stored in the ECU as a calibration parameter (e.g., 0.9 or 0.85). The ECU, upon obtaining N... set Then, execute: Warning threshold = λ·N set The calculation result is stored in another variable dedicated to the "early warning threshold," which is used in the early warning comparison logic in step S200.

[0097] Reference Figure 6 The dynamic basic security threshold N is calculated through a predetermined mapping relationship. set The steps include: refer to Figure 6 The dynamic basic security threshold N is calculated through a predetermined mapping relationship. setThe steps include: Step S600: Preset the baseline value L of the load characterization parameter. base and its corresponding baseline security threshold N base .

[0098] The baseline value L of the preset load characterization parameter base This is a parameter value representing the engine under a well-defined, typical, or moderate load condition, used as a reference point for dynamic calculations. Reference safety threshold N base This is a preset safe speed threshold corresponding to this reference load state, representing the highest safe speed the engine is allowed to reach under this typical operating condition. (Refer to...) Figure 6 The dynamic basic security threshold N is calculated through a predetermined mapping relationship. set The steps include: Step S600: Preset the baseline value L of the load characterization parameter. base and its corresponding baseline security threshold N base .

[0099] The baseline value L of the preset load characterization parameter base This is a parameter value representing the engine under a well-defined, typical, or moderate load condition, used as a reference point for dynamic calculations. Reference safety threshold N base It is a preset safe speed threshold corresponding to the reference load state, representing the highest safe speed that the engine can reach under this typical operating condition.

[0100] L base With N base As a set of core calibration parameters, these are determined during engine or complete machine type testing and written into the ECU's non-volatile memory. The determination method is as follows: Under engine bench or typical operating conditions, the engine is stably operated at a defined reference load point (e.g., intake pressure of 50 kPa or output shaft current of 10 A). Through engineering evaluation or safety analysis, a speed value that provides sufficient safety margin without being overly conservative under this load is determined as N. base (e.g., 4200 r / min). This pair (L) base N base The origin of the coordinate system is formed by the dynamic threshold adjustment.

[0101] Step S601: Calculate the current basic safety threshold N using a linear compensation model. set .

[0102] The linear compensation model is a mathematical model that assumes a linear relationship between load change and safe speed adjustment. It is used to adjust the baseline safe threshold N based on the deviation of the current actual load from the baseline load. baseMake proportional adjustments and calculate the dynamic threshold N that adapts to real-time operating conditions. set .

[0103] The ECU software can implement a function or calculation module based on this linear model, when N needs to be updated. set The module is invoked when (e.g., after obtaining new load parameters in step S500). The core of the model is: when the actual load L... current Above the baseline load L base When the engine experiences a higher mechanical load, the risk of damage during a runaway event is higher; therefore, the safety threshold N should be adjusted accordingly. set In N base Adjustments can be made downwards from the base level; conversely, adjustments can be maintained or slightly increased.

[0104] Step S602, , where L current The load characterization parameter value is obtained in real time, and k is the load-speed sensitivity coefficient preset according to the engine model.

[0105] (L current -L base The load () represents the deviation of the current load from the reference load, and can be positive or negative. k is the load-speed sensitivity coefficient, a constant greater than zero. Its physical meaning is the amount of compensation (in r / min) required to maintain the safe operating speed for a unit load change (e.g., a 1 kPa change in intake pressure). The magnitude of k determines the system's sensitivity to load changes.

[0106] Sensitivity coefficient k and L base N base The k-value is stored together and determined based on the engine's mechanical characteristics, durability, and safety strategy. For example, for engines with high reinforcement and strong durability, the k-value can be set smaller; for applications requiring more conservative protection, the k-value can be set larger. N is calculated in the ECU software. set The specific steps are as follows: 1. Calculate the load deviation ΔL = L current -L bas 2. Calculate the compensation amount ΔN = k·ΔL; 3. Calculate the dynamic threshold N. set =N base -ΔN. Calculation result N set As the output of step S501, it is used to update the flameout protection threshold in step S502.

[0107] Reference Figure 7 The steps following the engine shutdown operation also include: In step S700, a circular buffer is opened in the non-volatile memory to continuously record the engine's operating data. The operating data entries include at least a timestamp, engine speed, target throttle opening and actual throttle opening, and intake pressure.

[0108] A circular buffer is a first-in, first-out (FIFO) circular data storage structure. When it is full, new data overwrites the oldest data. This mechanism can continuously record the latest historical data with a fixed storage space. Continuous circular recording refers to the system continuously writing specified operating data into this buffer in chronological order during engine operation.

[0109] In the ECU's non-volatile memory (such as EEPROM or FRAM), a fixed-size area is pre-allocated as a circular buffer. Logically, this buffer is organized as an array of multiple "record units." Each record unit stores a set of operational data acquired at the same sampling time, including at least: the timestamp of the acquisition time (generated by the system clock), engine speed N, the target throttle opening issued by the ECU, the actual throttle opening fed back by the sensor, and the intake pressure. The ECU packages the latest values ​​of these variables into a record unit at a fixed recording cycle (e.g., 50 milliseconds) and writes it to the position pointed to by the "write pointer" in the buffer. The write pointer then cyclically moves to the next position. When the write pointer catches up with the "read pointer" (i.e., the buffer is full), the oldest data is automatically overwritten.

[0110] Step S701: When it is determined that the engine has entered a speed loss state and an emergency protection command is generated, lock and save the complete data segment within the first time period T1 before the trigger time and the second time period T2 after the trigger time.

[0111] Locking refers to preventing the data from being overwritten in a loop; saving refers to copying the locked data to a dedicated storage area or marking it specially. The first time period T1 and the second time period T2 define the duration of data that needs to be saved before the failure occurs (for analyzing the cause) and after the failure occurs (for observing the consequences), respectively.

[0112] When the ECU determines in step S102 or S302 that the engine has entered a speed control failure state, it immediately triggers a high-priority data saving interrupt service routine. The routine performs the following operations: 1. Mark the event point: Record the current write pointer position of the circular buffer. This position corresponds to the precise moment T when the fault determination takes effect. event 2. Calculate the data range: Based on the preset T1 (e.g., 2 seconds) and T2 (e.g., 0.5 seconds), and the system's recording period (e.g., 50 milliseconds), calculate the number of recording units that need to be saved: N1 = T1 / recording period (corresponding to data before the fault), N2 = T2 / recording period (corresponding to data after the fault); 3. Locking and dumping: Based on T...event Using the write pointer at time T as a reference, reverse the search and lock from T. event -N1 to T event All record units within the +N2 time window. To prevent this data from being overwritten by subsequent regular records, the system copies it from the circular buffer to a dedicated static storage area (such as a separate partition of non-volatile memory) for storing fault events. Alternatively, hardware or software mechanisms can be used to temporarily "freeze" write operations to the corresponding area in the circular buffer.

[0113] Step S702: Based on the saved data segments, a fault analysis report is automatically generated by analyzing the temporal relationship between the speed and the actual throttle opening. The report identifies at least one suspected root cause, including speed controller jamming, mechanical linkage component detachment, or speed sensor signal distortion.

[0114] The temporal relationship analysis refers to analyzing the curves of speed parameters and throttle parameters changing over time, examining their synergy, delay, or contradiction. Based on specific abnormal patterns and a pre-defined fault cause knowledge base, the most likely root cause of the fault is inferred.

[0115] When the system is idle or when requested by the connected host computer software diagnostic tool, the ECU performs offline analysis on the data segment saved in step S701. It calls the built-in fault diagnosis algorithm, which analyzes the data according to preset rules: 1. Pattern recognition: Checking the moment when the engine speed begins to rise abnormally (T...). rise 1. Near T, the actual change in throttle opening. 2. Rule judgment: If at T... rise Subsequently, if the actual throttle opening remains high or unchanged, while the target throttle opening has been commanded to decrease, the mode matching will be "speed regulator actuator stuck" (the actuator cannot respond to the retraction command); if in T rise If, at any given moment, the actual throttle opening abruptly drops to near zero or the mechanical lower limit, accompanied by a surge in engine speed, the mode matching is "mechanical linkage component detachment" (the cable or linkage breaks, the throttle loses mechanical constraint and returns to the idle position, while the governor may still be outputting the maximum throttle signal). If the displayed engine speed fluctuates abnormally or oscillates violently, while the actual throttle opening changes smoothly and conforms to the target command trend, the mode matching is "speed sensor signal distortion" (the sensor itself is faulty or the signal is severely interfered with). 3. Report Generation: Based on the matching results, the diagnostic algorithm formats a text report, including: the time of the fault event, the peak engine speed, the suspected root cause (e.g., "01-Government actuator stuck"), and a brief description of the key data features supporting this judgment. The report can be stored in the ECU for retrieval or sent directly to the diagnostic tool via the communication interface.

[0116] Based on the same inventive concept, embodiments of this application provide a method and system for preventing runaway engine shutdown in garden machinery, including: The acquisition module is used to acquire the engine's current speed, warning signals, auxiliary signals, and load characterization parameters. The auxiliary signals include at least one of vibration signals, oil pressure signals, and intake pressure signals. The load characterization parameters include at least one of intake manifold absolute pressure, power output shaft load current, or hydraulic system pressure. Memory, used to store the program for the runaway engine shutdown protection method of garden machinery; The processor and memory can load and execute programs to implement a method for preventing runaway engine shutdown in garden machinery.

[0117] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional modules is used as an example. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device, and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0118] This application provides a computer-readable storage medium storing a computer program that can be loaded by a processor and executed as a method for preventing runaway engine shutdown in garden machinery.

[0119] Computer storage media include, for example, USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, optical disks, and other media that can store program code.

[0120] Based on the same inventive concept, this application provides a smart terminal, including a memory and a processor, wherein the memory stores a computer program that can be loaded by the processor and executed as a method for protecting garden machinery from engine shutdown.

[0121] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional modules is used as an example. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device, and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0122] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Any feature disclosed in this specification (including the abstract and drawings) may be replaced by other equivalent or similar features unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is only one example of a series of equivalent or similar features.

Claims

1. A method for preventing engine failure in garden machinery, characterized in that, include: Real-time monitoring of the engine's current speed; The current speed is compared with the preset shutdown protection threshold, which is set to be higher than the highest set operating speed that the engine electronic speed control system can maintain under normal operating conditions. When the current engine speed exceeds the engine shutdown protection threshold, it is determined that the engine has entered a speed control failure state and an emergency protection command is immediately generated. Execute the emergency protection command, control the engine to shut down, and trigger the instrument panel to output an overspeed alarm message; The method also includes an early warning and composite judgment step: When the current speed exceeds a preset warning threshold, a warning signal is generated, wherein the warning threshold is set to be higher than the maximum set operating speed and lower than the flameout protection threshold; Based on the warning signal, obtain the average rate of increase of the current rotational speed per unit time since the warning signal was generated; When the current engine speed exceeds the shutdown protection threshold and the average rate of increase exceeds the preset acceleration threshold, the engine is determined to have entered a speed runaway state.

2. The method for protecting garden machinery from engine failure as described in claim 1, characterized in that, The steps following real-time monitoring of the engine's current speed also include: The auxiliary signals characterizing the mechanical operating status of the engine are acquired in real time, wherein the auxiliary signals include at least one of vibration signals, oil pressure signals, and intake pressure signals; After the auxiliary verification step, it is determined whether the current speed exceeds the shutdown protection threshold and whether the auxiliary signal exceeds its corresponding normal operating range. If the current engine speed exceeds the shutdown protection threshold and the auxiliary signal exceeds its normal operating range, the engine is determined to have entered a speed control failure state.

3. The method for protecting garden machinery from engine failure as described in claim 1, characterized in that, The steps for real-time monitoring of the engine's current speed include: The controller's timer unit captures the periodic pulse signal output by the engine speed sensor; The time interval Δt between the rising edges of consecutive pulses is calculated using the periodic measurement method. According to the preset pulse-rotation speed conversion coefficient K, the instantaneous rotation speed value N is calculated inst =K / Δt; The m instantaneous speed values acquired continuously are subjected to digital filtering processing to obtain a current speed N for subsequent comparison, the digital filtering processing including but not limited to sliding average filtering or median filtering, wherein m is calculated according to a preset filtering time window T f The instantaneous speed sampling period is calculated.

4. The method for protecting garden machinery from engine failure as described in claim 1, characterized in that, The engine shutdown protection threshold and / or warning threshold are adaptive thresholds that are dynamically adjusted based on the real-time operating status of the engine. The dynamic adjustment methods include: At least one engine load characterization parameter is acquired in real time, including intake manifold absolute pressure, power output shaft load current, or hydraulic system pressure. Based on the real-time values ​​of the load characterization parameters, the dynamic basic safety threshold N is calculated through a predetermined mapping relationship. set ; Set the flameout protection threshold to N. set ; Set the warning threshold to λ·N set , where λ is a preset proportionality coefficient, 0 < λ < 1.

5. The method for protecting garden machinery from engine stall during overdrive according to claim 4, characterized in that, The dynamic basic security threshold N is calculated through a predetermined mapping relationship. set The steps include: The baseline value L of the preset load characterization parameter base and its corresponding baseline safety threshold N base ; The current basic safety threshold N is calculated using a linear compensation model. set； , where L current The load characterization parameter value is obtained in real time, and k is the load-speed sensitivity coefficient preset according to the engine model.

6. The method for protecting garden machinery from engine failure as described in claim 1, characterized in that, The steps following controlling the engine to perform a shutdown operation also include: A circular buffer is created in the non-volatile memory to continuously and cyclically record the engine's operating data. The operating data entries include at least timestamps, engine speed, target throttle opening and actual throttle opening, and intake pressure. When it is determined that the engine has entered a speed control failure state and an emergency protection command is generated, the complete data segment within the first time period T1 before the trigger time and the second time period T2 after the trigger time is locked and saved. Based on the saved data segments, the system automatically generates a fault analysis report by analyzing the time sequence relationship between the speed and the actual throttle opening. The report identifies at least one possible root cause, which may include a stuck speed controller, a detached mechanical linkage component, or a distorted speed sensor signal.

7. A method and system for preventing runaway engine shutdown in garden machinery, characterized in that, include The acquisition module is used to acquire the engine's current speed, warning signals, auxiliary signals, and load characterization parameters. The auxiliary signals include at least one of vibration signals, oil pressure signals, and intake pressure signals. The load characterization parameters include at least one of intake manifold absolute pressure, power output shaft load current, or hydraulic system pressure. A memory for storing the program of the garden machinery overrun protection method as described in any one of claims 1 to 6; The processor and the program in the memory can be loaded and executed by the processor to implement the garden machinery runaway protection method as described in any one of claims 1 to 6.

8. A smart terminal, characterized in that, It includes a memory and a processor, wherein the memory stores a computer program that can be loaded by the processor and executed according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The computer program is stored that can be loaded by a processor and executed according to any one of claims 1 to 6.

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