Ignition control system and method suitable for ship engine knock prediction

Abstract

The invention relates to an ignition control system and method suitable for ship engine knock prediction, a vibration detection sensor detects a vibration signal of a knock part, a knock prediction unit receives the vibration signal in real time, and the change gradient of knock intensity grades of n continuous working cycles is calculated; and the change gradient serves as a knock trend predicted value and is compared with a preset safety threshold value, and dynamic optimization of the ignition angle is conducted. Knock monitoring and an ignition control system are deeply integrated, a knock sensor interface chip is used for collecting the knock intensity grade, a PID controller is designed, the trend is predicted according to the knock intensity gradient, a host control unit is triggered to delay the ignition angle, the knock occurrence rate can be effectively reduced, and dynamic optimization of the ignition angle is achieved. And the energy utilization efficiency in the combustion process is improved. The method is especially suitable for knocking prediction, ignition angle optimization and improvement of engine operation safety of new fuel marine engines such as methanol and ammonia.

Description

Technical Field

[0001] The present invention relates to the technical field of marine engine control, and in particular to an ignition control system and method suitable for marine engine knock prediction. Background Art

[0002] As the core power source of ships, the performance and reliability of marine engines directly impact their navigational safety and economic efficiency. Knock is a common abnormal combustion phenomenon during marine engine operation, which can lead to reduced 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 technology primarily relies on knock sensors to monitor knock signals and take appropriate control measures, such as delaying ignition, after knock is detected. This passive control method has a certain degree of hysteresis and cannot effectively prevent knock before it occurs. In addition, the control accuracy is limited, making it difficult to achieve fine adjustment of the ignition advance angle, thus affecting the control effect. In recent years, with the development of electronic control technology, knock control strategies based on closed-loop feedback have gradually attracted attention. This strategy prevents and suppresses the occurrence of knock by monitoring engine operating parameters in real time and adjusting the ignition advance angle according to a preset control algorithm. However, existing closed-loop feedback control strategies still have shortcomings in the coordination of knock prediction and ignition control, and cannot fully meet the requirements of high reliability and high fuel economy for marine engines. Summary of the Invention

[0004] To address the above problems, an ignition control system and method suitable for marine engine knock prediction are proposed. The method aims to deeply integrate knock monitoring with the ignition control system, use the knock sensor interface chip to collect the knock intensity level, and design a PID controller to predict the trend according to the knock intensity gradient, triggering the host control unit to delay the ignition angle, thereby avoiding knock and improving energy utilization and engine operation safety.

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

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

[0007] The knock monitoring and acquisition unit uses a knock sensor interface chip as a core component for knock monitoring and acquisition to extract 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 host control unit;

[0008] Each marine cylinder is equipped with an independent piezoelectric knock sensor and a knock monitoring and acquisition unit to form a distributed monitoring unit;

[0009] The knock analysis and prediction unit analyzes the collected knock intensity level data, uses gradient prediction and PID control algorithm to output the calculation results, transmits the calculation results to the engine host control unit, and triggers the engine host control unit to delay the ignition angle;

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

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

[0012] Preferably, the knock sensor interface chip in the knock monitoring and acquisition unit collects knock signals in real time, and the signal processing circuit built into the knock sensor interface chip amplifies, filters and shapes the collected knock signals, converts the charge signals into 0-5V analog voltage signals, and then undergoes analog-to-digital conversion, and the converted digital signals are used to extract the knock intensity level.

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

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

[0015]

[0016] Where n = 5, K i is the knock intensity level of the i-th working cycle;

[0017] If the gradient G>T safe , it is determined that the knock risk increases, triggering delayed ignition, T safe is the safety threshold;

[0018] If the gradient G < 0, it indicates that the knock tendency has weakened, and the ignition advance angle can be slightly increased, with each adjustment of ±1°CA and a maximum cumulative adjustment of no more than ±5°CA, to improve engine operation stability;

[0019] If 0≤G≤T safe , maintain the current ignition parameters unchanged;

[0020] After the delayed ignition is triggered, the PID controller calculates the ignition advance angle that needs to be adjusted based on the knock intensity gradient and the safety threshold and sends it to the engine host 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 unit control unit receives the ignition advance angle adjustment instruction transmitted by the knock analysis and prediction unit, the engine main unit control unit adjusts the ignition timing of the ignition actuator according to the instruction to realize dynamic control of the ignition advance angle, continues to monitor the knock intensity level after adjustment, updates the gradient value and judges subsequent adjustments again.

[0022] A knock prediction-based ignition control method comprises the following steps: a vibration detection sensor detects a vibration signal of a knock component; a knock prediction unit receives the vibration signal in real time, calculates a change gradient of the knock intensity level for n consecutive working cycles, and uses the change gradient as a knock trend prediction value for comparison with a preset safety threshold; if the knock trend prediction value exceeds the preset safety threshold, a trigger delayed ignition signal is output to a main control unit to adjust the ignition advance angle; if the knock trend prediction value does not exceed the preset safety threshold, a determination is made as to whether the change gradient is negative; if so, the ignition advance angle is increased according to the change gradient, and the advance ignition is adjusted to optimize fuel economy; if the change gradient is positive but does not exceed the preset safety threshold, the current ignition parameters are maintained; thus, dynamic optimization of the ignition angle is achieved, and energy utilization efficiency of the combustion process is improved.

[0023] The beneficial effects of the present invention are: The present invention is applicable to an ignition control system and method for marine engine knock prediction, effectively reducing the occurrence of knock, achieving dynamic optimization of the ignition angle, and improving the energy 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a block diagram of an ignition control system applicable to marine engine knock prediction according to the present invention;

[0025] Figure 2 This is a flow chart of the system control of the present invention. DETAILED DESCRIPTION

[0026] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0027] An ignition control system suitable for marine engine knock prediction, such as Figure 1 As shown in the figure, the system primarily consists of a knock sensor, a knock monitoring and acquisition unit, a knock analysis and prediction unit, an engine control unit, and an ignition actuator. The knock sensor is connected to the knock monitoring and acquisition unit via a shielded cable. CAN communication is used to transmit data between the knock monitoring and acquisition unit, the knock analysis and prediction unit, and the engine control unit. The knock analysis and prediction unit and the engine control unit also communicate via CAN. A hardwired connection is used between the engine control unit and the ignition actuator.

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

[0029] Knock monitoring and acquisition unit: The present invention uses a knock sensor interface chip as the core component for knock monitoring and acquisition. The high-performance knock sensor interface chip can accurately acquire parameters such as the amplitude and duration of the knock signal. The acquisition interface of the chip is connected to the knock sensor to acquire the knock signal in real time. The signal processing circuit built into the knock sensor interface chip amplifies, filters and shapes the collected knock signal, and converts the charge signal into a 0-5V analog voltage signal for subsequent analog-to-digital conversion and digital processing. The 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 unit control unit. The determination of the knock intensity level can be based on a comprehensive weighted calculation of the amplitude and duration.

[0030] Knock Analysis and Prediction Unit: The knock analysis and prediction unit in this invention utilizes gradient prediction and PID control algorithms. This unit analyzes the collected knock intensity level data, compares the gradient change value with the safety threshold, predicts knock trends, and adjusts the ignition advance angle. The knock analysis and prediction unit receives knock intensity level data transmitted by the knock monitoring and acquisition unit and calculates the knock intensity level gradient for five consecutive operating cycles. The intensity gradient is shown below:

[0031]

[0032] Where n = 5, K i is the knock intensity level of the i-th working cycle;

[0033] If the gradient G>T safe (preset safety threshold), the knock risk is determined to be increased and delayed ignition is triggered;

[0034] If the gradient G < 0, it indicates that the knock tendency has weakened, and the ignition advance angle can be slightly increased. Each adjustment cycle is adjusted by ±1°CA (CA is the crankshaft rotation angle), and the maximum cumulative adjustment does not exceed ±5°CA to improve engine operation stability.

[0035] If 0≤G≤T safe , keep the current ignition parameters unchanged.

[0036] After the delayed ignition is triggered, the ignition advance angle that needs to be adjusted is calculated by the PID controller based on the knock intensity gradient and the safety threshold. The input adjustment signal of the PID controller is the difference between the knock intensity gradient and the safety threshold. The safety threshold is calibrated by combining engine bench experiments and theoretical analysis, and can be dynamically adjusted according to the fuel type and engine operating conditions. The calculation result is transmitted to the engine main engine control unit, triggering the engine main engine control unit to delay the ignition angle. Engine main engine control unit: The engine main engine control unit in the present invention realizes the control of the ignition advance angle. When receiving the ignition advance angle adjustment instruction transmitted by the knock analysis and prediction unit, the engine main engine control unit adjusts the ignition time of the ignition actuator according to the instruction to realize dynamic control of the ignition advance angle. After the adjustment, the knock intensity level continues to be monitored, the gradient value is updated, and it is judged again whether further adjustment is needed.

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

[0038] like Figure 2 As shown in the system flow chart, the knock monitoring and acquisition unit collects the vibration signal of the combustion chamber of each cylinder of the ship. The knock monitoring and acquisition unit amplifies, filters and shapes the vibration signals of all cylinders, converts them into 0-5V analog voltage signals, and extracts the amplitude and duration parameters of the analog voltage signals to obtain the knock intensity level.

[0039] The knock monitoring and acquisition unit transmits the knock intensity level signal to the knock analysis and prediction unit and the engine main engine control unit. The knock analysis and prediction unit calculates the knock intensity level change gradient for five consecutive operating cycles to obtain a knock trend prediction value. If the value exceeds the preset safety threshold, the PID control algorithm calculates the ignition advance angle to be adjusted. The calculation result is sent to the engine main engine control unit, which outputs a control signal to the ignition actuator to adjust the ignition advance angle (delay ignition). If the knock trend prediction value does not exceed the preset safety threshold, the PID control unit determines whether the change gradient is negative. If so, the ignition advance angle is increased based on the change gradient to adjust the advance ignition to optimize fuel economy. If the change gradient is positive but does not exceed the preset safety threshold, the current ignition parameters are maintained.

[0040] The present invention integrates knock monitoring with the host control system to form a closed-loop feedback control system. The knock monitoring and acquisition unit, the knock analysis and prediction unit and the engine host control unit are connected through the CAN bus to achieve real-time data transmission and rapid response to control instructions. The high real-time performance and high reliability of the CAN bus are the key to supporting the closed-loop control of this system. By optimizing the PID control parameters, the control accuracy and response speed of the system are improved. The present invention predicts the knock trend by analyzing the changing gradient of the knock intensity level, realizes active prevention of knock, and avoids the occurrence of knock. According to the knock trend, the ignition advance angle is dynamically adjusted to improve the combustion efficiency and operational safety of the engine. The knock monitoring and host control system are deeply integrated to form a closed-loop feedback control system to improve the control accuracy and stability of the system. The use of high-performance knock sensor interface chips and optimized control algorithms can improve the reliability and anti-interference ability of the system.

[0041] The above-described embodiments merely represent specific implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. An ignition control system suitable for marine engine knock prediction, characterized in that: It includes knock sensor, knock monitoring and acquisition unit, knock analysis and prediction unit, engine host control unit and ignition actuator; The knock sensor is installed on the engine cylinder head or cylinder block, converts the high-frequency vibration signal of the combustion chamber into a charge signal, and the charge signal is sent to the knock monitoring and acquisition unit; The knock monitoring and acquisition unit uses a knock sensor interface chip as a core component for knock monitoring and acquisition to extract 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 host control unit; Each marine cylinder is equipped with an independent piezoelectric knock sensor and a knock monitoring and acquisition unit to form a distributed monitoring unit; The knock analysis and prediction unit analyzes the collected knock intensity level data, uses gradient prediction and PID control algorithm to output the calculation results, transmits the calculation results to the engine host control unit, and triggers the engine host control unit to delay the ignition angle; The engine main engine control unit: realizes dynamic control of the ignition advance angle; The ignition actuator ensures the accurate execution of the ignition control instruction.

2. The ignition control system for marine engine knock prediction according to claim 1, characterized in that: The knock sensor interface chip in the knock monitoring and acquisition unit collects knock signals in real time. The signal processing circuit built into the knock sensor interface chip amplifies, filters and shapes the collected knock signals, converts the charge signals into 0-5V analog voltage signals, and then undergoes analog-to-digital conversion. The converted digital signals are used to extract the knock intensity level.

3. The ignition control system suitable for marine engine knock prediction according to claim 1 or 2, characterized in that: CAN communication is used to transmit data between the knock monitoring and acquisition unit, the knock analysis and prediction unit, and the engine host control unit; the knock analysis and prediction unit and the engine host control unit use CAN communication for transmission.

4. An ignition control method suitable for marine engine knock prediction, characterized in that: Establish an ignition control system suitable for marine engine knock prediction as described in claim 3, wherein the knock analysis and prediction unit receives the knock intensity level data transmitted by the knock monitoring and acquisition unit, and calculates the change gradient of the knock intensity level for five consecutive working cycles. The intensity gradient is expressed as follows: Where n = 5, K i is the knock intensity level of the i-th working cycle; If the gradient G>T safe , it is determined that the knock risk increases, triggering delayed ignition, T safe is the safety threshold; If the gradient G < 0, it indicates that the knock tendency has weakened, and the ignition advance angle can be slightly increased, with each adjustment of ±1°CA and a maximum cumulative adjustment of no more than ±5°CA, to improve engine operation stability; If 0≤G≤T safe , maintain the current ignition parameters unchanged; After the delayed ignition is triggered, the PID controller calculates the ignition advance angle that needs to be adjusted based on the knock intensity gradient and the safety threshold and sends it to the engine host control unit. The input adjustment signal of the PID controller is the difference between the knock intensity gradient and the safety threshold.

5. The ignition control method for marine engine knock prediction according to claim 4, characterized in that: When the engine main engine control unit receives the ignition advance angle adjustment instruction transmitted by the knock analysis and prediction unit, the engine main engine control unit adjusts the ignition timing of the ignition actuator according to the instruction to realize dynamic control of the ignition advance angle, continues to monitor the knock intensity level after adjustment, updates the gradient value and determines the subsequent adjustment again.

6. An ignition control method based on knock prediction, characterized in that: The vibration detection sensor detects the vibration signal of the knock component, and the knock prediction unit receives the vibration signal in real time, calculates the change gradient of the knock intensity level for n consecutive working cycles, and uses the change gradient as the knock trend prediction value to compare with the preset safety threshold. If the knock trend prediction value exceeds the preset safety threshold, the trigger delayed 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 change gradient is negative. If so, the ignition advance angle is increased according to the change gradient, and the advance ignition is adjusted to optimize fuel economy; if the change gradient is positive but does not exceed the preset safety threshold, the current ignition parameters are maintained; dynamic optimization of the ignition angle is achieved to improve the energy utilization efficiency of the combustion process.

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