Marine diesel engine piston ring life prediction method and system

Abstract

The invention discloses a marine diesel engine piston ring life prediction method and system, and relates to the technical field of marine diesel engines, and the method comprises the following steps: obtaining a historical power time sequence of a marine diesel engine from the start of operation to the current date, and inputting the historical power time sequence into a degradation model of a piston ring, obtaining the current abrasion loss of the piston ring on the marine diesel engine; the set maximum abrasion loss of the piston ring on the marine diesel engine is subtracted from the current abrasion loss, and the future maximum abrasion loss is obtained; encoding the course of the ship and the season of the ship, and inputting the encoded course and season into a pre-trained power prediction model to obtain a future power time sequence; and solving the residual life of the piston ring on the marine diesel engine based on the future time sequence power and the future maximum abrasion loss. The actual operation condition of the diesel engine is considered, and the piston ring service life prediction accuracy is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of marine diesel engines, in particular to a marine diesel engine piston ring life prediction method and system. BACKGROUND

[0002] The marine diesel engine piston ring is a core component to ensure the efficient operation of the diesel engine. When the marine diesel engine is running, the piston ring is in a complex environment of high temperature, high pressure, high corrosion and strong vibration, and it has to bear alternating loads for a long time. Therefore, the life of the piston ring needs to be predicted to determine whether the piston ring needs to be replaced.

[0003] Directly monitoring the real-time wear state of the piston ring (such as thickness change or surface damage, etc.) requires installing high-precision sensors inside the cylinder, which is technically difficult, costly, and the sensors are easily disturbed by harsh environments (such as signal distortion caused by oil stains and high temperature). At the same time, the life of the piston ring is affected by many factors such as fuel quality, lubrication conditions, combustion products (such as sulfides) and load fluctuations.

[0004] In engineering practice, the fixed life method is often used to determine the life of the marine diesel engine piston ring. This method simplifies the complex factors into a linear relationship of "time-life" by statistical historical data and experience, which deviates greatly from the actual situation, resulting in a great reduction in the accuracy of the final piston ring life prediction. SUMMARY

[0005] Based on the defects of the prior art, the present application provides a marine diesel engine piston ring life prediction method and system, which solves the problem of low accuracy in predicting the life of the marine diesel engine piston ring by using the fixed life method.

[0006] The present application adopts the following technical solutions: In a first aspect, the present application provides a marine diesel engine piston ring life prediction method, comprising the following steps: Obtain the historical power time sequence of the marine diesel engine from the start of operation to the current date, and input the historical power time sequence into the degradation model of the piston ring to obtain the current wear of the piston ring on the marine diesel engine; wherein the degradation model is constructed by the wear coefficient of the marine diesel engine, the time-varying power and the hardness of the piston ring; Subtract the set maximum wear of the piston ring on the marine diesel engine from the current wear to obtain the future maximum wear; Encode the route and season of the ship and input it into the pre-trained power prediction model to obtain the future power time sequence; Solve the remaining life of the piston ring on the marine diesel engine based on the future time sequence power and the future maximum wear.

[0007] Preferably, the degradation model is specifically as follows: ; In the formula, is the piston ring wear amount from 0 to time t , is the wear coefficient, is the piston ring hardness, is the time-varying power, is the time variable.

[0008] Preferably, different wear coefficients are used for different types of diesel engines.

[0009] Preferably, the power prediction model is an LSTM model, and the pre-training of the LSTM model includes the following steps: Extracting power time series data under different routes and seasons from the ship historical operation database; Encoding different routes and seasons to obtain corresponding route features and season features; training the LSTM model with different route features and season features as input and corresponding power time series data as output to obtain a pre-trained power prediction model; the power prediction model is specifically as follows: P = f ( R , S ); In the formula, R represents the route feature, S represents the season feature, P is the power.

[0010] Preferably, the remaining life of the piston ring on the ship diesel engine is solved by a life solving formula, and the life solving formula is specifically as follows: ; In the formula, RUL is the remaining life, is the future power time series, is the future maximum wear amount, is the current date.

[0011] In a second aspect, the present application provides a ship diesel engine piston ring life prediction system, comprising: An acquisition module is configured to acquire historical power time series of a ship diesel engine from the start of operation to the current date, and input the historical power time series into a degradation model of a piston ring to obtain a current wear amount of the piston ring on the ship diesel engine; wherein the degradation model is constructed by a wear coefficient, a time-varying power and a piston ring hardness of the ship diesel engine; A difference module is configured to subtract a set maximum wear amount of the piston ring on the ship diesel engine from the current wear amount to obtain a future maximum wear amount. a prediction module, configured to input the route and season where the ship is located into a pre-trained power prediction model after coding to obtain a future power time sequence; a calculation module, configured to solve the remaining life of the piston ring on the ship diesel engine based on the future time sequence power and the future maximum wear amount.

[0012] Compared with the prior art, the above at least one technical scheme of the present application can achieve the following beneficial effects: The present application constructs a degradation model through the wear coefficient of the ship diesel engine, the time-varying power and the hardness of the piston ring, first inputs the historical power time sequence of the ship diesel engine from the start of operation to the current date into the degradation model of the piston ring to obtain the current wear amount of the piston ring, and obtains the future maximum wear amount by subtracting the set maximum wear amount from the current wear amount. The present application dynamically quantifies the future allowable wear allowance by setting the difference between the maximum allowable wear amount and the current wear amount of the piston ring. Then, the route and season where the ship is located are coded and input into a pre-trained power prediction model to obtain a future power time sequence. In different routes and seasons, the operating conditions of the ship diesel engine are different, and the present application considers the influence of the route and season on the operating conditions of the diesel engine to predict the power closer to the actual operating conditions. Finally, the remaining life of the piston ring is obtained based on the future time sequence power and the future maximum wear amount. The present application considers the actual operating conditions of the diesel engine, and improves the accuracy of the piston ring life prediction. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0014] Figure 1 The flowchart of a ship diesel engine piston ring life prediction method of the present application. DETAILED DESCRIPTION

[0015] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0016] In the current ship operation and management practice, the fixed life method is used to determine the service life of the piston ring of the ship diesel engine, and then a fixed period is obtained. The piston ring is replaced according to the fixed period. This replacement mode does not consider the actual operating condition of the ship diesel engine. If the diesel engine is in good load condition for a long time, the forced replacement of the piston ring according to the fixed period will cause waste of the piston ring and additional maintenance cost, and will also increase the risk of damage to the diesel engine due to improper disassembly and inspection operation; if the diesel engine is in severe or high load condition for a long time, the forced replacement of the piston ring according to the fixed period will cause the piston ring to fail, resulting in serious damage to the diesel engine.

[0017] Referring to Figure 1 , the present application provides a ship diesel engine piston ring life prediction method, comprising the following steps: S1: obtaining the historical power time sequence of the ship diesel engine from the start of operation to the current date, and inputting the historical power time sequence into the degradation model of the piston ring to obtain the current wear amount of the piston ring on the ship diesel engine.

[0018] The piston ring wear amount calculation formula is shown in formula (1): (1); Wherein, is the piston ring wear amount; is the wear coefficient, a dimensionless parameter representing the friction characteristics of the material, which is affected by the lubrication condition, and the basic value is calibrated through bench test; is the indicated power, which represents the effective power of a single cylinder of the diesel engine in a single cycle, and reflects the mechanical load strength; is the hardness of the piston ring, which is a material inherent property, measured by Rockwell Hardness C Scale (HRC), and the typical value is 50-60HRC.

[0019] For a multi-cylinder diesel engine, the first cylinder indicated power The calculation formula is shown in formula (2): (2); Wherein, is the time-varying power, is the time variable.

[0020] From formula (1) and formula (2), the degradation model of the piston ring can be obtained, as shown in formula (3): (3); In the formula, is the piston ring wear amount from 0 to time t .

[0021] This embodiment takes a two-stroke diesel engine as an example. For a two-stroke diesel engine, the wear coefficient k will be affected by the metal particle content in the fuel, the cylinder oil viscosity, and the oil injection rate. The corrected wear coefficient can be calculated by the following formula (4): (4); In the formula, is the base wear coefficient under the rated operating condition, is the metal particle concentration in the fuel, is the critical concentration threshold, is the actual viscosity, is the design viscosity, is the actual oil injection rate, is the rated oil injection rate, is the empirical index.

[0022] Calculate the current cumulative wear amount: (5); In the formula, is the current cumulative wear amount, is the current date, is the historical power time series.

[0023] Discrete calculation of historical power integral using trapezoidal method or Simpson method to obtain historical power time series .

[0024] S2: Subtract the current wear amount from the set maximum wear amount of the piston ring on the marine diesel engine to obtain the future maximum wear amount.

[0025] S3: Input the route and season of the ship into the pre-trained power prediction model to obtain the future power time series.

[0026] Data collection: Extract the main engine power time series data under different routes (such as coastal / ocean) and seasons (spring / summer / autumn / winter) from the ship historical operation database. Encode different routes and seasons to obtain corresponding route features and seasonal features.

[0027] Model structure: Use LSTM neural network, input layer is route feature and seasonal feature, output layer is future power sequence.

[0028] Training process: Take the historical power time series and the corresponding route and season labels as the training set, and optimize the model parameters by minimizing the mean square error (MSE) of the predicted power and the actual power.

[0029] Establish a diesel engine power prediction model combining route features and seasonal features. The power prediction model is an LSTM model, and the model function is shown in formula (6): P = f ( R , S )(6); Where, R Indicates route characteristics, S Indicates seasonal characteristics.

[0030] Predicting the future using LSTM Time period power series .

[0031] S4: Calculate the remaining life of the piston ring on the ship diesel engine based on the future time-series power and the future maximum wear.

[0032] To predict the remaining life RUL, the piston ring wear must satisfy the following life solution formula (7): (7); Where, is the maximum wear amount, is the current date. The solution method is to gradually accumulate the future power integral until , piston ring failure.

[0033] Or, if the power is approximately constant , P 0 is the average value of the predicted power, then: (8).

[0034] Example It is known that the operating route of a container ship in 2024 is Shanghai-Ningbo-Shenzhen-Shanghai, with a 10-day shift. Its operating data is shown in Table 1. The piston ring hardness is 50HRC, and the wear coefficient is: , failure threshold: .

[0035] Table 1 Operation data of a container in 2024

[0036] Calculated by formula (5): The current wear amount is: .

[0037] Assuming the corrected wear coefficient: , the route remains unchanged, and the average power of the main engine from January to March 2025 can be predicted to be 6000KW. The predicted life of the piston ring is: .

[0038] Based on the same concept, the application also provides a ship diesel engine piston ring life prediction system, comprising an acquisition module, a difference module, a prediction module and a calculation module.

[0039] The acquisition module is used for acquiring a historical power time sequence of the ship diesel engine from the start of operation to the current date, and inputting the historical power time sequence into a degradation model of the piston ring to obtain a current wear amount of the piston ring on the ship diesel engine; wherein the degradation model is constructed by a wear coefficient of the ship diesel engine, a time-varying power and a piston ring hardness.

[0040] The difference module is used for subtracting the set maximum wear amount of the piston ring on the ship diesel engine from the current wear amount to obtain a future maximum wear amount.

[0041] The prediction module is used for inputting a route and a season where the ship is located into a pre-trained power prediction model after coding to obtain a future power time sequence.

[0042] The calculation module is used for solving the remaining life of the piston ring on the ship diesel engine based on the future time sequence power and the future maximum wear amount.

[0043] The application can dynamically predict the remaining life of the piston ring by real-time sensing of the diesel engine operating conditions (such as load, fuel quality and lubrication state and the like), avoiding "over maintenance" or "insufficient maintenance" caused by fixed period replacement. For example, when the diesel engine is in a low load good condition for a long time, the replacement period can be extended to reduce unnecessary disassembly and inspection; when the condition is deteriorated, early warning and shortening of the replacement period can prevent sudden failures.

[0044] The piston ring life prediction method considering the diesel engine operating conditions can track the wear trend of the piston ring in real time, identify abnormal wear risks (such as rapid wear under high load) in advance, avoid accidents such as cylinder gas leakage, fuel leakage and mechanical damage caused by piston ring functional failure, reduce unnecessary spare parts replacement and downtime, and improve ship operation efficiency.

[0045] Although the preferred embodiments of the application have been described, those skilled in the art can make further changes and modifications to the embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all changes and modifications falling within the scope of the application.

[0046] Obviously, those skilled in the art can make various modifications and changes to the application without departing from the spirit and scope of the application. Thus, if these modifications and changes of the application fall within the scope of the claims of the application and their equivalent technologies, the application also intends to include these modifications and changes.

Claims

1. A method for predicting the life of a marine diesel engine piston ring, characterized in that: The following steps are involved: Obtain the historical power time series of the marine diesel engine from the start of operation to the current date, and input the historical power time series into the piston ring degradation model to obtain the current wear amount of the piston ring on the marine diesel engine. The degradation model is constructed based on the wear coefficient, time-varying power, and piston ring hardness of the marine diesel engine. The maximum wear amount in the future is obtained by subtracting the set maximum wear amount of the piston ring on the marine diesel engine from the current wear amount; The ship's route and season are encoded and input into the pre-trained power prediction model to obtain the future power time series; The remaining life of the piston ring on a marine diesel engine is calculated based on the future sequential power and the future maximum wear.

2. A method for predicting the life of a marine diesel engine piston ring according to claim 1, characterized in that: The degradation model is specifically as follows: ； Where, From 0 to time t The piston ring wear, is the wear coefficient, is the piston ring hardness, is the time-varying power, is the time variable.

3. A method for predicting the life of a marine diesel engine piston ring according to claim 2, characterized in that: Different wear coefficients need to be used for different types of diesel engines.

4. The method for predicting the life of a marine diesel engine piston ring according to claim 1, wherein: The power prediction model is an LSTM model, and its pre-training includes the following steps: Extract power time series data under different routes and seasons from the ship's historical operation database; Different routes and seasons are encoded to obtain corresponding route characteristics and season characteristics. The LSTM model is trained using different route characteristics and season characteristics as input and corresponding power time series data as output to obtain a pre-trained power prediction model. The power prediction model is specifically shown below: P = f （ R , S ）； Where, R Indicates route characteristics, S Indicates seasonal characteristics. P For power.

5. The method for predicting the life of a marine diesel engine piston ring according to claim 2, wherein: The remaining life of the piston ring on the marine diesel engine is solved by the life solution formula, which is specifically as follows: ； Where, RUL is the remaining life, For future power timing, is the maximum future wear amount, is the current date.

6. A marine diesel engine piston ring life prediction system, characterized in that: include: An acquisition module is used to obtain the historical power time series of the marine diesel engine from the start of operation to the current date, and input the historical power time series into the piston ring degradation model to obtain the current wear amount of the piston ring on the marine diesel engine; wherein, the degradation model is constructed based on the wear coefficient of the marine diesel engine, the time-varying power and the piston ring hardness; A subtraction module is used to subtract the set maximum wear amount of the piston ring on the ship diesel engine from the current wear amount to obtain the future maximum wear amount; The prediction module is used to encode the ship's route and season and input them into the pre-trained power prediction model to obtain the future power time series; The calculation module is used to solve the remaining life of the piston ring on the ship diesel engine based on the future time series power and the future maximum wear amount.

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