Ignition control system and method for knock prediction in marine engines

Abstract

This invention relates to an ignition control system and method for predicting knock in marine engines. A vibration detection sensor detects vibration signals from knocking components. A knock prediction unit receives these vibration signals in real time and calculates the gradient of knock intensity levels over n consecutive operating cycles. This gradient is used as a knock trend prediction value and compared with a preset safety threshold to dynamically optimize the ignition angle. The aim is to deeply integrate knock monitoring with the ignition control system, utilize a knock sensor interface chip to collect knock intensity levels, and design a PID controller to trigger the main control unit to delay the ignition angle based on the knock intensity gradient prediction trend. This effectively reduces the knock incidence rate, achieves dynamic optimization of the ignition angle, and improves the energy utilization efficiency of the combustion process. It is particularly suitable for knock prediction, ignition angle optimization, and improved engine operating safety in marine engines using new fuels such as methanol and ammonia.

Description

Technical Field

[0001] This invention relates to the field of marine engine control technology, and in particular to an ignition control system and method suitable for predicting knock in marine engines. Background Technology

[0002] Marine engines, as the core power source of ships, directly impact navigation safety and economic efficiency through their performance and reliability. Knocking, a common abnormal combustion phenomenon during marine engine operation, can lead to decreased engine power, increased fuel consumption, component damage, and even serious safety accidents. Therefore, effective prediction and control of marine engine knock is crucial for ensuring safe engine operation and improving energy efficiency.

[0003] Existing marine engine knock control technologies primarily rely on knock sensors to monitor knock signals and implement corresponding control measures, such as delayed ignition, after knock is detected. This passive control method suffers from a certain degree of lag, failing to effectively prevent knock before it occurs, and its control precision is limited, making it difficult to finely adjust the ignition advance angle, thus affecting control effectiveness. In recent years, with the development of electronic control technology, knock control strategies based on closed-loop feedback have gradually gained attention. This strategy monitors engine operating parameters in real time and adjusts the ignition advance angle according to a preset control algorithm to prevent and suppress knock. However, existing closed-loop feedback control strategies still have shortcomings in the coordination between knock prediction and ignition control, failing to fully meet the requirements of high reliability and high fuel economy for marine engines. Summary of the Invention

[0004] To address the aforementioned issues, an ignition control system and method suitable for predicting knock in marine engines are proposed. The aim is to deeply integrate knock monitoring with the ignition control system, utilize a knock sensor interface chip to collect knock intensity levels, and design a PID controller to trigger the main engine control unit to delay the ignition angle based on the knock intensity gradient prediction trend, thereby avoiding knock, improving energy utilization and engine operating safety.

[0005] The technical solution of the present invention is: an ignition control system suitable for predicting knock in marine engines, comprising a knock sensor, a knock monitoring and acquisition unit, a knock analysis and prediction unit, an engine main control unit, and an ignition actuator;

[0006] The knock sensor is installed on the engine cylinder head or cylinder block and converts the high-frequency vibration signal of the combustion chamber into an electric charge signal, which is then sent to the knock monitoring and acquisition unit.

[0007] The knock monitoring and acquisition unit uses a knock sensor interface chip as the core component for knock monitoring and acquisition, extracts the knock intensity level including amplitude and duration parameters, and transmits the knock intensity level data to the knock analysis and prediction unit and the engine main control unit.

[0008] Each marine cylinder is equipped with an independent piezoelectric knock sensor and a knock monitoring and acquisition unit, forming a distributed monitoring unit.

[0009] The knock analysis and prediction unit analyzes the collected knock intensity level data, uses gradient prediction and PID control algorithms to output the calculation results, and transmits them to the engine main control unit to trigger the engine main control unit to delay the ignition angle.

[0010] The engine main control unit: enables dynamic control of the ignition advance angle;

[0011] The ignition actuator ensures the accurate execution of ignition control commands.

[0012] Preferably, the detonation sensor interface chip in the detonation monitoring and acquisition unit acquires detonation signals in real time. The acquired detonation signals are amplified, filtered, and shaped by the signal processing circuit built into the detonation sensor interface chip, converting the charge signal into a 0-5V analog voltage signal. After analog-to-digital conversion, the converted digital signal is used to extract the detonation intensity level.

[0013] Preferably, the knock monitoring and acquisition unit, the knock analysis and prediction unit, and the engine main control unit transmit data via CAN communication; the knock analysis and prediction unit and the engine main control unit transmit data via CAN communication.

[0014] An ignition control method for predicting knock in marine engines is provided. An ignition control system suitable for predicting knock in marine engines is established. The knock analysis and prediction unit receives knock intensity level data transmitted by the knock monitoring and acquisition unit, and calculates the gradient of knock intensity level change over five consecutive operating cycles. The intensity gradient is expressed as follows:

[0015]

[0016] Where n = 5, K i The detonation intensity level for the i-th working cycle;

[0017] If gradient G>T safe If the risk of detonation increases, delayed ignition is triggered, T safe This is a safety threshold;

[0018] If the gradient G < 0, it indicates that the knocking trend is weakened, and the ignition advance angle can be increased slightly, with each adjustment being ±1°CA and the maximum cumulative adjustment not exceeding ±5°CA, in order to improve the engine's operational stability.

[0019] If 0 ≤ G ≤ T safe The current ignition parameters remain unchanged;

[0020] After triggering delayed ignition, the ignition advance angle to be adjusted is calculated by the PID controller based on the knock intensity gradient and the safety threshold and sent to the engine main control unit. The input adjustment signal of the PID controller is the difference between the knock intensity gradient and the safety threshold.

[0021] Furthermore, when the engine main control unit receives the ignition advance angle adjustment command transmitted by the knock analysis and prediction unit, the engine main control unit adjusts the ignition timing of the ignition actuator according to the command to achieve dynamic control of the ignition advance angle. After adjustment, it continues to monitor the knock intensity level, updates the gradient value, and judges the subsequent adjustment again.

[0022] An ignition control method based on knock prediction is disclosed. A vibration detection sensor detects the vibration signal of a knock component. A knock prediction unit receives the vibration signal in real time and calculates the gradient of knock intensity level changes over n consecutive working cycles. This gradient is used as a knock trend prediction value and compared with a preset safety threshold. If the knock trend prediction value exceeds the preset safety threshold, a trigger delay ignition signal is output to the main control unit to adjust the ignition advance angle. If the knock trend prediction value does not exceed the preset safety threshold, it is determined whether the gradient is negative. If so, the ignition advance angle is increased according to the gradient to optimize fuel economy. If the gradient is positive but does not exceed the preset safety threshold, the current ignition parameters are maintained. This achieves dynamic optimization of the ignition angle, improving the energy utilization efficiency of the combustion process.

[0023] The beneficial effects of this invention are as follows: This invention is applicable to the ignition control system and method for predicting knock in marine engines, which can effectively reduce the knock occurrence rate, achieve dynamic optimization of the ignition angle, and improve the energy utilization efficiency of the combustion process. It is particularly suitable for knock prediction, ignition angle optimization, and improvement of engine operation safety in marine engines using new fuels such as methanol and ammonia. Attached Figure Description

[0024] Figure 1 This is a block diagram of the ignition control system for predicting knock in marine engines according to the present invention.

[0025] Figure 2 This is a system control flowchart of the present invention. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0027] An ignition control system suitable for predicting knock in marine engines, such as Figure 1 As shown, the system mainly includes a knock sensor, a knock monitoring and acquisition unit, a knock analysis and prediction unit, an engine main control unit, and an ignition actuator. The knock sensor is connected to the knock monitoring and acquisition unit via a shielded cable. Data is transmitted between the knock monitoring and acquisition unit, the knock analysis and prediction unit, and the engine main control unit via CAN communication. The knock analysis and prediction unit and the engine main control unit also use CAN communication for data transmission. The engine main control unit and the ignition actuator are connected by a hard wire.

[0028] Knock Sensor: Each cylinder in marine engines is equipped with an independent piezoelectric knock sensor and a knock monitoring and acquisition unit, forming a distributed monitoring unit. This aims to improve the accuracy of single-cylinder knock detection and reduce the false alarm rate. The piezoelectric knock sensor converts the high-frequency vibrations caused by knocking in the combustion chamber into an electrical signal. The sensor is typically installed on the engine cylinder head or cylinder block to maximize the capture of vibration signals from the combustion chamber.

[0029] Knock Monitoring and Acquisition Unit: This invention utilizes a knock sensor interface chip as the core component for knock monitoring and acquisition. This high-performance knock sensor interface chip can accurately acquire parameters such as the amplitude and duration of knock signals. The chip's acquisition interface is connected to the knock sensor to acquire knock signals in real time. Through the signal processing circuit built into the knock sensor interface chip, the acquired knock signals are amplified, filtered, and shaped, converting the charge signal into a 0-5V analog voltage signal for subsequent analog-to-digital conversion and digital processing. This unit extracts the knock intensity level, including amplitude and duration parameters. The processed knock intensity level data is transmitted to the knock analysis and prediction unit and the engine main control unit. The knock intensity level can be determined based on a weighted calculation of amplitude and duration.

[0030] Knock Analysis and Prediction Unit: The knock analysis and prediction unit in this invention employs gradient prediction and PID control algorithms. This unit analyzes the collected knock intensity level data, compares the gradient change values ​​with the safety threshold difference, predicts the knock trend, and adjusts the ignition advance angle. The knock analysis and prediction unit receives knock intensity level data transmitted from the knock monitoring and acquisition unit, calculates the knock intensity level change gradient for five consecutive operating cycles, and the intensity gradient is expressed as follows:

[0031]

[0032] Where n = 5, K i The detonation intensity level for the i-th working cycle;

[0033] If gradient G>T safe If the preset safety threshold is reached, the risk of knocking is determined to be increased, and delayed ignition is triggered.

[0034] If the gradient G < 0, it indicates that the knocking trend is weakened, and a slight increase in the ignition advance angle is allowed. Each adjustment cycle is adjusted by ±1°CA (CA is the crankshaft rotation angle), and the maximum cumulative adjustment does not exceed ±5°CA, in order to improve the engine's operating stability.

[0035] If 0 ≤ G ≤ T safe The current ignition parameters will remain unchanged.

[0036] After triggering delayed ignition, the required ignition advance angle is calculated by a PID controller based on the knock intensity gradient and a safety threshold. The input adjustment signal to the PID controller is the difference between the knock intensity gradient and the safety threshold. The safety threshold is calibrated through a combination of engine bench experiments and theoretical analysis, and can be dynamically adjusted according to fuel type and engine operating conditions. The calculation result is transmitted to the engine main control unit, triggering the engine main control unit to delay the ignition angle. Engine Main Control Unit: In this invention, the engine main control unit controls the ignition advance angle. When it receives the ignition advance angle adjustment command transmitted by the knock analysis and prediction unit, the engine main control unit adjusts the ignition timing of the ignition actuator according to the command, achieving dynamic control of the ignition advance angle. After adjustment, the knock intensity level is continuously monitored, the gradient value is updated, and it is determined again whether further adjustment is needed.

[0037] Ignition actuator: This typically includes components such as an ignition coil and spark plugs. The ignition actuator enables precise control of parameters such as the ignition advance angle, ensuring accurate execution of control commands.

[0038] like Figure 2 The system flowchart shown shows that the knock monitoring and acquisition unit collects the combustion chamber vibration signal of each cylinder in the marine engine. After amplifying, filtering and shaping the vibration signal of all cylinders, the knock monitoring and acquisition unit converts it into a 0-5V analog voltage signal and extracts the amplitude and duration parameters of the analog voltage signal to obtain the knock intensity level.

[0039] The knock monitoring and acquisition unit sends the knock intensity level signal to the knock analysis and prediction unit and the engine control unit. The knock analysis and prediction unit calculates the knock intensity level change gradient over five consecutive operating cycles to obtain the knock trend prediction value. If it exceeds a preset safety threshold, the PID control algorithm calculates the ignition advance angle that needs to be adjusted, and the calculation result is sent to the engine control unit. The engine control unit outputs a control signal to the ignition actuator to adjust the ignition advance angle (retard ignition). If the knock trend prediction value does not exceed the preset safety threshold, it checks whether the change gradient is negative. If so, it increases the ignition advance angle according to the change gradient to adjust the ignition advance and optimize fuel economy. If the change gradient is positive but does not exceed the preset safety threshold, the current ignition parameters are maintained.

[0040] This invention integrates knock monitoring with the engine control system to form a closed-loop feedback control system. The knock monitoring and acquisition unit, knock analysis and prediction unit, and engine control unit are connected via a CAN bus to achieve real-time data transmission and rapid response to control commands. The high real-time performance and high reliability of the CAN bus are key to supporting the closed-loop control of this system. By optimizing PID control parameters, the system's control accuracy and response speed are improved. This invention analyzes the gradient of knock intensity levels to predict knock trends, achieving proactive knock prevention and avoiding knock occurrence. Based on knock trends, the ignition advance angle is dynamically adjusted to improve engine combustion efficiency and operational safety. Deep integration of knock monitoring with the engine control system forms a closed-loop feedback control system, improving system control accuracy and stability. The use of a high-performance knock sensor interface chip and optimized control algorithms enhances system reliability and anti-interference capabilities.

[0041] The embodiments described above merely illustrate specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An ignition control method suitable for knock prediction of a marine engine, characterized by, An ignition control system suitable for predicting knock in marine engines is established. The system includes a knock sensor, a knock monitoring and acquisition unit, a knock analysis and prediction unit, an engine main control unit, and an ignition actuator. The knock sensor is installed on the engine cylinder head or cylinder block and converts the high-frequency vibration signal of the combustion chamber into an electric charge signal, which is then sent to the knock monitoring and acquisition unit. The knock monitoring and acquisition unit uses a knock sensor interface chip as the core component for knock monitoring and acquisition, extracts the knock intensity level including amplitude and duration parameters, and transmits the knock intensity level data to the knock analysis and prediction unit and the engine main unit control unit. Each marine cylinder is equipped with an independent piezoelectric knock sensor and a knock monitoring and acquisition unit, forming a distributed monitoring unit. The knock analysis and prediction unit analyzes the collected knock intensity level data, uses gradient prediction and PID control algorithms to output the calculation results, and transmits them to the engine main control unit to trigger the engine main control unit to delay the ignition angle. The engine main control unit: enables dynamic control of the ignition advance angle; The ignition actuator ensures the accurate execution of ignition control commands; The method includes: the detonation analysis and prediction unit receiving detonation intensity level data transmitted by the detonation monitoring and acquisition unit, and calculating the change gradient of the detonation intensity level over five consecutive working cycles. The intensity gradient is expressed as follows: wherein , K i is the knock intensity rating of the i-th work cycle; If the gradient then knock risk is determined to be rising, triggering retarded ignition, T safe is a safety threshold; If the gradient , indicating that the knock tendency is weakened, the ignition advance angle is allowed to be slightly increased, and each adjustment , the maximum cumulative adjustment does not exceed , to improve the engine operation stability; If , maintain the current firing parameters unchanged; After triggering delayed ignition, the ignition advance angle to be adjusted is calculated by the PID controller based on the knock intensity gradient and the safety threshold, and then sent to the engine main control unit. The input adjustment signal of the PID controller is the difference between the knock intensity gradient and the safety threshold.

2. The ignition control method for knock prediction of a marine engine according to claim 1, characterized in that, When the engine main control unit receives the ignition advance angle adjustment command transmitted by the knock analysis and prediction unit, the engine main control unit adjusts the ignition timing of the ignition actuator according to the command to achieve dynamic control of the ignition advance angle. After adjustment, it continues to monitor the knock intensity level, updates the gradient value, and judges the subsequent adjustment again.

3. The ignition control method for knock prediction of a marine engine according to claim 1, characterized by, A vibration detection sensor detects the vibration signal of the knock component. The knock prediction unit receives the vibration signal in real time and calculates the gradient of the knock intensity level over n consecutive working cycles. The gradient is used as the knock trend prediction value and compared with a preset safety threshold. If the knock trend prediction value exceeds the preset safety threshold, a trigger delay ignition signal is output to the main control unit to adjust the ignition advance angle. If the knock trend prediction value does not exceed the preset safety threshold, it is determined whether the gradient is negative. If so, the ignition advance angle is increased according to the gradient to adjust the ignition advance and optimize fuel economy. If the gradient is positive but does not exceed the preset safety threshold, the current ignition parameters are maintained. This achieves dynamic optimization of the ignition angle and improves the energy utilization efficiency of the combustion process.

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