CN118152739A - Cylinder pressure peak value online prediction method and system for linear internal combustion power generation system - Google Patents
Cylinder pressure peak value online prediction method and system for linear internal combustion power generation system Download PDFInfo
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Abstract
The invention provides a cylinder pressure peak value online prediction method and a cylinder pressure peak value online prediction system for a linear internal combustion power generation system, which relate to the technical field of data processing, and comprise the following steps: acquiring a cylinder pressure signal and a piston displacement signal of a linear internal combustion power generation system in real time; noise reduction processing is carried out on the cylinder pressure signal and the piston displacement signal; marking key characteristic points reflecting the combustion state of the cylinder in a cylinder pressure signal under the current thermodynamic cycle; extracting and temporarily storing general features of related information describing a cylinder pressure peak value according to time and pressure information of key feature points; substituting the time characteristic and the slope characteristic into a characteristic regression equation respectively, and predicting the occurrence time of the current thermodynamic cycle cylinder pressure peak value and the slope of the straight line; calculating a linear equation of a straight line where the cylinder pressure peak value is located according to the slope of the straight line where the predicted cylinder pressure peak value is located; substituting the occurrence time of the predicted cylinder pressure peak value into a linear equation to obtain a prediction result of the current thermodynamic cycle cylinder pressure peak value.
Description
Technical Field
The invention relates to the technical field of data processing, in particular to a cylinder pressure peak value online prediction method and system of a linear internal combustion power generation system.
Background
The linear internal combustion power generation system is a novel high-efficiency energy conversion system formed by coupling a free piston engine and a linear motor. The system takes a free piston engine as an internal combustion engine, and the generated power directly acts on a motion assembly consisting of a piston and a linear motor rotor to convert the internal energy generated by fuel combustion into the kinetic energy of the motion assembly and then into electric energy for output. Different from the traditional ignition type and compression ignition type internal combustion engines, the linear internal combustion power generation system has no crank connecting rod structure, the piston track does not need to follow the running track of the traditional internal combustion engine type sinusoidal curve, and only the piston track moves in the opposite cylinders in a linear manner, so that the mechanical limit in the running process is greatly reduced, the friction resistance is reduced, and the thermal efficiency and the comprehensive efficiency of the system are remarkably improved.
Although the linear internal combustion power generation system has the advantages of compact power form structure, short energy transmission chain, flexible and adjustable compression ratio of the system, adaptability of multi-fuel and multi-fuel models and the like, the system still has the defects of poor controllability of a piston operation dead center, obvious difference of internal combustion states of a cylinder under continuous different cycles, frequent occurrence of fire and knocking phenomena and the like, which influence continuous operation of a free piston engine, and continuous power generation of a linear motor. In summary, it is necessary to propose a scientific research method with guiding significance, which identifies and predicts abnormal combustion phenomena of the free piston engine, and achieves the purposes of timely intervening abnormal combustion and realizing stable operation of the internal combustion system.
Currently, there are numerous methods for predicting the pressure in a cylinder of an internal combustion system using data-driven based on historical operating data of a large number of test equipment. However, the phenomenon of severe periodic variation of the combustion state in the cylinder of the linear internal combustion power generation system causes that the cylinder pressure under different thermodynamic cycles is not regular and repeatable, and particularly the peak pressure and peak time of each cycle are remarkably different. Therefore, the pressure prediction method applied to the conventional internal combustion system is difficult to be effectively migrated to the linear internal combustion power generation system.
Disclosure of Invention
The invention provides a cylinder pressure peak value online prediction method and a cylinder pressure peak value online prediction system for a linear internal combustion power generation system, aiming at solving the technical problems that in the prior art, the cylinder pressure under different thermodynamic cycles is not regular and repeatable due to the phenomenon of severe periodic variation of the combustion state in a cylinder of the linear internal combustion power generation system, and particularly the peak pressure and peak time of each cycle are remarkably different, so that the pressure prediction method in the traditional internal combustion system is difficult to effectively migrate to the linear internal combustion power generation system.
The technical scheme provided by the embodiment of the invention is as follows:
First aspect:
the cylinder pressure peak value online prediction method of the linear internal combustion power generation system provided by the embodiment of the invention comprises the following steps:
s1: acquiring a cylinder pressure signal and a piston displacement signal of a linear internal combustion power generation system in real time;
s2: noise reduction processing is carried out on the cylinder pressure signal and the piston displacement signal;
s3: marking key feature points reflecting the combustion state of the cylinder in the cylinder pressure signal under the current thermodynamic cycle according to the cylinder pressure signal and the piston displacement signal after the noise reduction treatment;
S4: extracting and temporarily storing general features of related information describing a cylinder pressure peak value according to the time and pressure information of the key feature points, wherein the general features comprise a first time feature, a first slope feature, a second time feature and a second slope feature;
s5: carrying out regression analysis according to the first time feature, the first slope feature, the second time feature and the second slope feature to obtain a feature regression equation;
S6: substituting the time characteristic and the slope characteristic into the characteristic regression equation respectively, and predicting the occurrence time of the current thermodynamic cycle cylinder pressure peak value and the slope of the straight line;
S7: calculating a linear equation of a straight line where the cylinder pressure peak value is located according to the slope of the straight line where the predicted cylinder pressure peak value is located;
s8: substituting the occurrence time of the predicted cylinder pressure peak value into the linear equation to obtain a prediction result of the current thermodynamic cycle cylinder pressure peak value.
Second aspect:
The cylinder pressure peak value online prediction system of the linear internal combustion power generation system provided by the embodiment of the invention comprises the following components:
A processor;
and a memory having stored thereon computer readable instructions which, when executed by the processor, implement the cylinder pressure peak online prediction method of the linear internal combustion power generation system according to the first aspect.
The technical scheme provided by the embodiment of the invention has the beneficial effects that at least:
In the invention, aiming at the phenomenon that parameters such as in-cylinder pressure time histories and the like are different between different continuous cycles and between different cylinders of a linear internal combustion power generation system, the invention combines cylinder pressure signals and piston position information to identify the peak value of in-cylinder pressure of a free piston engine under different thermodynamic cycles in advance, acquires key characteristics capable of representing the in-cylinder peak pressure time and amplitude characteristics, constructs a characteristic regression equation to realize the prediction of peak pressure and peak time, takes the predicted peak pressure and peak time as the judgment basis of the in-cylinder combustion state in the current cycle, timely identifies and even intervenes the abnormal state such as unburned or incomplete combustion in the cylinder, and has simple prediction process based on regression analysis, accurate prediction effect and strong practicability.
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In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic flow chart of a cylinder pressure peak value online prediction method of a linear internal combustion power generation system provided by an embodiment of the invention;
FIG. 2 is a schematic diagram of a prediction result of a combustion pressure peak of a linear internal combustion power generation system according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of the slope characteristic linear regression result of the method for online predicting the cylinder pressure peak value of the general linear internal combustion power generation system according to the embodiment of the invention;
Fig. 4 is a schematic diagram of a pressure peak prediction result of a general online prediction method for cylinder pressure peak values of a linear internal combustion power generation system according to an embodiment of the present invention;
Fig. 5 is a schematic structural diagram of an online cylinder pressure peak value prediction system of a linear internal combustion power generation system according to an embodiment of the present invention.
Detailed Description
The technical scheme of the invention is described below with reference to the accompanying drawings.
In embodiments of the invention, words such as "exemplary," "such as" and the like are used to mean serving as an example, instance, or illustration. Any embodiment or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments or designs. Rather, the term use of an example is intended to present concepts in a concrete fashion. Furthermore, in embodiments of the present invention, the meaning of "and/or" may be that of both, or may be that of either, optionally one of both.
In order to make the technical problems, technical solutions and advantages to be solved more apparent, the following detailed description will be given with reference to the accompanying drawings and specific embodiments.
Referring to fig. 1 of the specification, a flow chart of an online cylinder pressure peak value prediction method of a linear internal combustion power generation system provided by an embodiment of the invention is shown.
Referring to fig. 2 of the specification, a schematic diagram of a combustion pressure peak prediction result of a linear internal combustion power generation system according to an embodiment of the present invention is shown.
Referring to fig. 3 of the specification, a schematic diagram of the slope characteristic linear regression result of the method for online predicting the cylinder pressure peak value of the general linear internal combustion power generation system is shown.
Referring to fig. 4 of the specification, a schematic diagram of a pressure peak prediction result of a general online prediction method for cylinder pressure peak values of a linear internal combustion power generation system according to an embodiment of the invention is shown.
The embodiment of the invention provides a cylinder pressure peak value online prediction method of a linear internal combustion power generation system, which can be realized by cylinder pressure peak value online prediction equipment of the linear internal combustion power generation system, wherein the cylinder pressure peak value online prediction equipment of the linear internal combustion power generation system can be a terminal or a server. The process flow of the cylinder pressure peak value online prediction method of the linear internal combustion power generation system can comprise the following steps:
S1: and acquiring a cylinder pressure signal and a piston displacement signal of the linear internal combustion power generation system in real time.
In one possible embodiment, S1 is specifically: and a cylinder pressure sensor arranged on the cylinder cover and a displacement sensor arranged on the piston linkage component are used for respectively acquiring a cylinder pressure signal and a piston displacement signal in the linear internal combustion power generation system in real time.
Optionally, the displacement sensor comprises: hall type crank position sensor, photoelectric type crank position sensor, electromagnetic type crank position sensor, magnetic grating ruler, grating ruler and/or rotary position sensor.
S2: and carrying out noise reduction treatment on the cylinder pressure signal and the piston displacement signal.
It should be noted that, considering that the original cylinder pressure signal and the piston displacement signal acquired by the cylinder pressure sensor and the displacement sensor are affected by the working environment, the vibration of the machine body, and other external influences, the original cylinder pressure signal and the piston displacement signal are often doped with severe noise information. In order to improve the signal-to-noise ratio of the cylinder pressure signal and the piston displacement signal and reduce the interference of noise information on the accuracy of a combustion pressure prediction algorithm of the linear internal combustion power generation system.
In one possible embodiment, S2 is specifically: and carrying out noise reduction treatment on the cylinder pressure signal and the piston displacement signal through moving average noise reduction, median filtering noise reduction, wavelet noise reduction and/or wavelet packet decomposition.
S3: and marking key characteristic points reflecting the combustion state of the cylinder in the cylinder pressure signal under the current thermodynamic cycle according to the cylinder pressure signal and the piston displacement signal after the noise reduction treatment.
Optionally, the key feature points include: ignition point, peak point of highest cylinder pressure rise rate, and the like.
It will be appreciated that the piston of the linear internal combustion power generation system transitions from a state of communication with the external link to an approximately pure compression state during movement from the top dead center of the opposite cylinder to the firing position of the opposite cylinder. In the above stage, the pressure of the mixed gas in the cylinder is approximately equal under different thermodynamic cycles. Therefore, the main factors affecting the peak value of the cylinder pressure are the mixing state of the combustible gas and the fuel at the ignition timing, the diffusion and diffusion of the flame, and the like.
In summary, from the movement of the piston to the ignition position, a plurality of key feature points capable of reflecting the in-cylinder combustion state are defined, which are the ignition point, the highest cylinder pressure rise rate point and the peak point, respectively.
In one possible embodiment, S3 specifically includes:
S301: and marking the ignition time t ig under the current thermodynamic cycle according to the piston displacement signal after the noise reduction processing and the ignition point, and marking the ignition pressure P ig corresponding to the ignition time in the cylinder pressure signal.
For example, if the predetermined firing position of the linear internal combustion power generation system is 23 mm, the firing signal will trigger when the displacement of the piston reaches 23 mm. The time at which the ignition signal is triggered is designated as ignition time t ig, and the corresponding ignition pressure P ig on the cylinder pressure signal curve is then marked as a function of the ignition time.
The ignition timing is a start point of the combustion process of the engine, and the mark ignition timing helps to determine the start time of combustion. Meanwhile, the recorded ignition pressure can reflect the mixing state of fuel and air at the beginning of combustion, and a basis is provided for analysis of the subsequent combustion process.
S302: and marking the highest point O Dmax of the cylinder pressure rising rate in the cylinder pressure signal of the current thermodynamic cycle according to the cylinder pressure signal after the noise reduction treatment, and recording the time t Dmax and the pressure P Dmax corresponding to the highest point.
The highest point of the cylinder pressure rise rate generally corresponds to the time when combustion is most intense, and is one of the key points of the combustion process. Recording the time and pressure at this point helps to accurately predict the time of occurrence of the cylinder pressure peak and reflects the intensity of combustion.
The method for solving the cylinder pressure increase rate includes, but is not limited to, a method capable of effectively calculating the pressure increase rate such as a differential pressure method in a continuous equal sampling interval or a maximum pressure increase rate identification method based on a vibration signal.
S303: the moment and the pressure of the ignition point O ig and the highest point O Dmax of the cylinder pressure rising rate under the current thermodynamic cycle are temporarily stored.
According to the invention, the time and the pressure of the ignition point O ig and the highest point O Dmax of the cylinder pressure elevation rate under the current thermodynamic cycle are temporarily stored, so that the combustion process of the engine can be monitored and analyzed, the performance and the efficiency of the power generation system are improved, and the basis is provided for the identification and the intervention of abnormal states.
S4: and extracting and temporarily storing general features of related information describing the cylinder pressure peak value according to the time and pressure information of the key feature points.
It can be appreciated that the linear internal combustion power generation system has a severe periodic variation phenomenon, and combustion states in cylinders are different under each thermodynamic cycle, and particularly, peak pressures and peak moments under different cycles have significant differences. The necessary premise for realizing the peak pressure prediction is to obtain key characteristics which can effectively describe the peak pressure and the peak time of the current cycle under different thermodynamic cycles.
Wherein the general features include a first temporal feature, a first slope feature, a second temporal feature, and a second slope feature.
Optionally, the first time feature is specifically: the relative time interval between the highest pressure rise rate point O Dmax and the ignition point O ig:
Δt＝tDmax-tig
Where Δt represents the first time characteristic, t Dmax represents the time corresponding to the highest pressure rise rate point O Dmax, and t ig represents the time corresponding to the ignition point O ig.
By the first time feature, it is possible to know how long after ignition the highest point of pressure rise is reached. This is critical to determining the combustion rate and the speed of the combustion process.
Optionally, the first slope characteristic is specifically: the slope of the line between the highest pressure rise rate point O Dmax and the ignition point O ig:
Where k represents the first slope characteristic, P Dmax represents the pressure corresponding to the highest point O Dmax of the pressure rise rate, and P ig represents the pressure corresponding to the ignition point O ig.
The slope indicates the rate of pressure change, i.e., the intensity and speed of combustion. The greater the slope, the more intense the combustion.
Optionally, the second time feature is specifically: the relative time interval between peak point O max and ignition point O ig in successive thermodynamic cycles:
ΔT＝tmax-tig
Where Δt represents the second time characteristic, and T max represents the time corresponding to the peak point O max.
The second time characteristic indicates the time from ignition to peak in the entire combustion process. This is important to understand the duration of the entire combustion process.
Optionally, the second slope is characterized specifically by: the slope of the line formed by peak point O max and ignition point O ig:
Where K represents the second slope characteristic and P max represents the pressure corresponding to peak point O max.
In the invention, the general characteristics of the cylinder pressure peak value are extracted and temporarily stored, which is helpful for comprehensively knowing the running state of the engine, optimizing the performance of the engine, and timely finding and solving the potential problems, thereby improving the overall performance and reliability of the linear internal combustion power generation system.
S5: and carrying out regression analysis according to the first time feature, the first slope feature, the second time feature and the second slope feature to obtain a feature regression equation.
Specifically, the characteristic regression equation includes a linear regression equation with respect to a time characteristic and a linear regression equation with respect to a slope characteristic.
The linear regression analysis is a prediction method with simple operation and strong feasibility. The precondition for realizing the prediction based on the linear regression analysis is that the independent variable and the dependent variable of the regression equation have strong linear correlation. For the time characteristics, the first time characteristic deltat is taken as an independent variable, and the second time characteristic deltat is taken as an independent variable. For the slope characteristics, the first slope characteristic K is taken as an independent variable, and the second slope characteristic K of the peak is taken as an independent variable.
In one possible implementation, S5 specifically includes sub-steps S501 and S502:
s501: taking the first time feature as an input variable of the linear regression equation of the time feature, and taking the second time feature as a corresponding output to obtain the linear regression equation about the time feature:
Wherein, Representing the predicted value of the second temporal feature, β 0、β1 represents the regression coefficient.
S502: taking the first slope characteristic as an input variable of the slope characteristic linear regression equation and the second slope characteristic as a corresponding output, obtaining the linear regression equation about the slope characteristic:
Wherein, And a predicted value representing the second slope characteristic, and alpha 0、α1 represents a regression coefficient.
In the invention, the change rule of the pressure in the combustion process can be known more deeply through regression analysis of the time characteristics and the slope characteristics. This is important in studying the dynamic process of combustion, optimizing the timing of ignition, etc.
S6: and substituting the time characteristic and the slope characteristic into a characteristic regression equation respectively, and predicting the occurrence time of the current thermodynamic cycle cylinder pressure peak value and the slope of the straight line.
In one possible implementation, S6 specifically includes sub-steps S601 and S602:
s601: substituting the first time characteristic in the current thermodynamic cycle into a linear regression equation related to the time characteristic, and predicting to obtain a second time characteristic.
S602: substituting the first slope characteristic in the current thermodynamic cycle into a linear regression equation related to the slope characteristic, and predicting to obtain a second slope characteristic.
In the present invention, by predicting the second time characteristic and the second slope characteristic, the occurrence time and slope of the current thermodynamic cycle cylinder pressure peak can be predicted in real-time operation. This facilitates real-time monitoring and control of the combustion process of the engine.
S7: and calculating a linear equation of a straight line where the cylinder pressure peak value is located according to the slope of the straight line where the predicted cylinder pressure peak value is located.
In one possible embodiment, S7 is specifically: the linear equation of the straight line where the cylinder pressure peak value is calculated according to the following formula:
Wherein, Representing a predicted cylinder pressure peak value, and P ig represents an ignition pressure.
S8: substituting the occurrence time of the predicted cylinder pressure peak value into a linear equation to obtain a prediction result of the current thermodynamic cycle cylinder pressure peak value.
According to the invention, the real-time prediction of the current thermodynamic cycle cylinder pressure peak value can be realized, and the prediction result is applied to engine control and optimization, so that the performance, combustion efficiency and stability of the engine are improved.
The invention provides a general online prediction method for cylinder pressure peak value of a linear internal combustion power generation system. Aiming at the phenomenon that the pressure peak value in the combustion chamber of the linear internal combustion power generation system is difficult to predict due to the severe cycle fluctuation characteristic, the time and frequency characteristics capable of representing the pressure characteristic of the peak value in the cylinder are obtained by combining the cylinder pressure signal and the piston position information acquired in real time, and the prediction of the pressure peak value in each cycle combustion chamber is realized based on linear regression analysis. And respectively recording the time and the corresponding pressure of the piston moving to the preset ignition position, the highest in-cylinder pressure change rate, the peak in-cylinder pressure and other three characteristic points according to the piston displacement time domain curve and the cylinder pressure time domain curve under different continuous cycles in the stable power generation stage. The relative time interval between the highest pressure change rate point, the peak value point and the ignition point is taken as two time characteristics, and the relative slope of the line segment formed by the highest pressure change rate, the peak value pressure and the ignition pressure is taken as two slope characteristics. Then, based on the strong linear correlation of the time characteristic and the slope characteristic respectively, and by utilizing regression analysis, a linear regression equation of the time characteristic and the slope characteristic is calculated respectively. Finally, when the combustion pressure does not reach the maximum value, only substituting the time and slope characteristics between the ignition point and the highest point of the pressure change rate into a linear regression equation respectively, and calculating the relative time interval between the ignition point and the peak point and the slope of the formed straight line to realize the prediction of the pressure peak value in the combustion chamber. In addition, the multi-signal fusion analysis of the linear internal combustion power generation system is considered, the prediction process is simple, the prediction effect is accurate, and the practicability is high.
The technical scheme provided by the embodiment of the invention has the beneficial effects that at least:
In the invention, aiming at the phenomenon that parameters such as in-cylinder pressure time histories and the like are different between different continuous cycles and between different cylinders of a linear internal combustion power generation system, the invention combines cylinder pressure signals and piston position information to identify the peak value of in-cylinder pressure of a free piston engine under different thermodynamic cycles in advance, acquires key characteristics capable of representing the in-cylinder peak pressure time and amplitude characteristics, constructs a characteristic regression equation to realize the prediction of peak pressure and peak time, takes the predicted peak pressure and peak time as the judgment basis of the in-cylinder combustion state in the current cycle, timely identifies and even intervenes the abnormal state such as unburned or incomplete combustion in the cylinder, and has simple prediction process based on regression analysis, accurate prediction effect and strong practicability.
Referring to fig. 5 of the specification, a schematic diagram of a cylinder pressure peak value online prediction system of a linear internal combustion power generation system is shown.
The invention also provides a cylinder pressure peak value online prediction system 20 of the linear internal combustion power generation system, which is applied to the cylinder pressure peak value online prediction method of the linear internal combustion power generation system, and comprises the following steps:
A processor 201.
The memory 202, the memory 202 stores computer readable instructions that, when executed by the processor 201, implement the cylinder pressure peak online prediction method of the linear internal combustion power generation system as in the method embodiment.
The cylinder pressure peak value online prediction system 20 of the linear internal combustion power generation system provided by the invention can execute the cylinder pressure peak value online prediction method of the linear internal combustion power generation system, and achieve the same or similar technical effects, and in order to avoid repetition, the invention is not repeated.
The technical scheme provided by the embodiment of the invention has the beneficial effects that at least:
In the invention, aiming at the phenomenon that parameters such as in-cylinder pressure time histories and the like are different between different continuous cycles and between different cylinders of a linear internal combustion power generation system, the invention combines cylinder pressure signals and piston position information to identify the peak value of in-cylinder pressure of a free piston engine under different thermodynamic cycles in advance, acquires key characteristics capable of representing the in-cylinder peak pressure time and amplitude characteristics, constructs a characteristic regression equation to realize the prediction of peak pressure and peak time, takes the predicted peak pressure and peak time as the judgment basis of the in-cylinder combustion state in the current cycle, timely identifies and even intervenes the abnormal state such as unburned or incomplete combustion in the cylinder, and has simple prediction process based on regression analysis, accurate prediction effect and strong practicability.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
The following points need to be described:
(1) The drawings of the embodiments of the present invention relate only to the structures related to the embodiments of the present invention, and other structures may refer to the general designs.
(2) In the drawings for describing embodiments of the present invention, the thickness of layers or regions is exaggerated or reduced for clarity, i.e., the drawings are not drawn to actual scale. It will be understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "under" another element, it can be "directly on" or "under" the other element or intervening elements may be present.
(3) The embodiments of the invention and the features of the embodiments can be combined with each other to give new embodiments without conflict.
The present invention is not limited to the above embodiments, but the scope of the invention is defined by the claims.
Claims (10)
1. The on-line cylinder pressure peak value prediction method for the linear internal combustion power generation system is characterized by comprising the following steps of:
s1: acquiring a cylinder pressure signal and a piston displacement signal of a linear internal combustion power generation system in real time;
s2: noise reduction processing is carried out on the cylinder pressure signal and the piston displacement signal;
s3: marking key feature points reflecting the combustion state of the cylinder in the cylinder pressure signal under the current thermodynamic cycle according to the cylinder pressure signal and the piston displacement signal after the noise reduction treatment;
S4: extracting and temporarily storing general features of related information describing a cylinder pressure peak value according to the time and pressure information of the key feature points, wherein the general features comprise a first time feature, a first slope feature, a second time feature and a second slope feature;
s5: carrying out regression analysis according to the first time feature, the first slope feature, the second time feature and the second slope feature to obtain a feature regression equation;
S6: substituting the time characteristic and the slope characteristic into the characteristic regression equation respectively, and predicting the occurrence time of the current thermodynamic cycle cylinder pressure peak value and the slope of the straight line;
S7: calculating a linear equation of a straight line where the cylinder pressure peak value is located according to the slope of the straight line where the predicted cylinder pressure peak value is located;
s8: substituting the occurrence time of the predicted cylinder pressure peak value into the linear equation to obtain a prediction result of the current thermodynamic cycle cylinder pressure peak value.
2. The online cylinder pressure peak value prediction method of a linear internal combustion power generation system according to claim 1, wherein the S1 specifically is:
And a cylinder pressure sensor arranged on the cylinder cover and a displacement sensor arranged on the piston linkage component are used for respectively acquiring a cylinder pressure signal and a piston displacement signal in the linear internal combustion power generation system in real time.
3. The on-line cylinder pressure peak value prediction method of a linear internal combustion power generation system according to claim 2, wherein the displacement sensor includes: hall type crank position sensor, photoelectric type crank position sensor, electromagnetic type crank position sensor, magnetic grating ruler, grating ruler and/or rotary position sensor.
4. The online cylinder pressure peak value prediction method of the linear internal combustion power generation system according to claim 1, wherein the S2 is specifically:
And carrying out noise reduction treatment on the cylinder pressure signal and the piston displacement signal through moving average noise reduction, median filtering noise reduction, wavelet noise reduction and/or wavelet packet decomposition.
5. The on-line cylinder pressure peak value prediction method of a linear internal combustion power generation system according to claim 1, wherein the key feature points include: ignition point, highest cylinder pressure rise rate point and peak point; the step S3 specifically comprises the following steps:
S301: marking the ignition time t ig under the current thermodynamic cycle according to the noise-reduced piston displacement signal and the ignition point, and marking the ignition pressure P ig corresponding to the ignition time in a cylinder pressure signal;
S302: marking a highest point O Dmax of the cylinder pressure rising rate in the cylinder pressure signal of the current thermodynamic cycle according to the cylinder pressure signal after the noise reduction treatment, and recording a time t Dmax and a pressure P Dmax corresponding to the highest point;
S303: and temporarily storing the moment and the pressure of the ignition point O ig and the highest point O Dmax of the cylinder pressure rising rate under the current thermodynamic cycle.
6. The online cylinder pressure peak prediction method of a linear internal combustion power generation system according to claim 5, wherein the first time characteristic is specifically: the relative time interval between the pressure rise rate highest point O Dmax and the ignition point O ig:
Δt＝tDmax-tig
wherein Δt represents a first time characteristic, t Dmax represents a time corresponding to the highest point O Dmax of the pressure rise rate, and t ig represents a time corresponding to the ignition point O ig;
The first slope is characterized by specifically: the slope of the straight line formed by the highest point O Dmax of the pressure rise rate and the ignition point O ig:
Where k represents a first slope characteristic, P Dmax represents a pressure corresponding to the highest point O Dmax of the pressure rise rate, and P ig represents a pressure corresponding to the ignition point O ig;
the second time characteristic is specifically: the relative time interval between peak point O max and the ignition point O ig in successive thermodynamic cycles:
ΔT＝tmax-tig
Wherein Δt represents the second time characteristic, and T max represents the time corresponding to the peak point O max;
The second slope is characterized by: the slope of the straight line formed by the peak point O max and the ignition point O ig:
Where K represents the second slope characteristic and P max represents the pressure corresponding to peak point O max.
7. The online cylinder pressure peak prediction method of the linear internal combustion power generation system according to claim 6, wherein S5 specifically comprises:
S501: taking the first time feature as an input variable of a time feature linear regression equation, and taking the second time feature as a corresponding output to obtain a linear regression equation about the time feature:
Wherein, Predicted values representing the second temporal feature, β 0、β1 representing the regression coefficients;
S502: and taking the first slope characteristic as an input variable of a slope characteristic linear regression equation, and taking the second slope characteristic as a corresponding output to obtain a linear regression equation about the slope characteristic:
Wherein, And a predicted value representing the second slope characteristic, and alpha 0、α1 represents a regression coefficient.
8. The online cylinder pressure peak prediction method of the linear internal combustion power generation system according to claim 7, wherein S6 specifically includes:
S601: substituting the first time feature in the current thermodynamic cycle into a linear regression equation related to the time feature, and predicting to obtain a second time feature;
S602: substituting the first slope characteristic in the current thermodynamic cycle into a linear regression equation related to the slope characteristic, and predicting to obtain a second slope characteristic.
9. The online cylinder pressure peak value prediction method of the linear internal combustion power generation system according to claim 8, wherein the S7 specifically is:
The linear equation of the straight line where the cylinder pressure peak value is calculated according to the following formula:
Wherein, Representing a predicted cylinder pressure peak value, and P ig represents an ignition pressure.
10. An on-line cylinder pressure peak value prediction system of a linear internal combustion power generation system, comprising:
A processor;
A memory having stored thereon computer readable instructions which, when executed by the processor, implement the cylinder pressure peak online prediction method of a linear internal combustion power generation system as defined in any one of claims 1 to 9.
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