A method for characterizing and optimizing the operation trajectory of a linear internal combustion power generation system

Abstract

The invention discloses a method for characterizing and optimizing the running trajectory of a linear internal combustion power generation system, and belongs to the technical field of linear internal combustion power generation systems. The method comprises: selecting an optimization evaluation index from multi-dimensional evaluation indexes; obtaining mechanical constraints and basic working conditions of the linear internal combustion power generation system; designing a B-spline thermodynamic cycle trajectory characterization with some trajectory decision points as key points; calculating the running trajectory characterization of the linear internal combustion power generation system; setting constraints of trajectory decision points and boundary conditions of trajectory decision point parameters in combination with mechanical constraints, basic working conditions and the running trajectory characterization of the linear internal combustion power generation system; establishing an objective function according to the optimization evaluation index; constructing a motion trajectory model to be optimized; optimizing the running trajectory model to be optimized, and determining the optimal decision point parameters of the motion trajectory model to be optimized according to the objective function; using the running trajectory characterization of the linear internal combustion power generation system to perform recursive calculation to obtain the optimal profile, and calculating multiple parameter values ​​of the optimal decision point.

Description

Technical Field

[0001] The present invention belongs to the technical field of linear internal combustion power generation systems, and in particular relates to a method for characterizing and optimizing an operating trajectory of a linear internal combustion power generation system. Background Art

[0002] The linear internal combustion power generation system is a new type of high-efficiency energy conversion system coupled by a free piston engine and a linear motor. It uses a free piston engine as the prime mover and directly converts the combustion chemical energy into electrical energy output through the reciprocating motion of the piston and motor moving parts. Compared with traditional piston engines, this power form has a compact structure, a short energy transmission chain, a flexible and adjustable system compression ratio, and adaptability to multiple fuels and multiple combustion models. The system can achieve distributed drive through a modular layout and has broad application prospects.

[0003] Unlike traditional internal combustion systems, linear internal combustion power generation systems are not constrained by a crank-connecting rod mechanism and have fewer mechanical restrictions during operation. The piston's operating trajectory does not have to follow the traditional sinusoidal trajectory, which makes it possible to improve the system's thermal efficiency, overall efficiency, and economy. At the same time, linear motors are the main energy conversion devices in linear internal combustion power generation systems, which makes it possible to adjust the system's operating trajectory.

[0004] At present, the trajectory adjustment of linear internal combustion power generation systems is mostly aimed at a single goal, that is, the thermal efficiency of the internal combustion engine. The description of the target profile is mostly concentrated on the functional representation of the sine-like profile of the virtual crankshaft. In addition, the optimization process is complicated, and the thermal-dynamic correlation and system operation characteristics are not considered during the optimization process. As a result, the optimization results are often not significant or difficult to implement in practical applications, and effective and targeted trajectory optimization has not been carried out based on the operating characteristics of the linear internal combustion power generation system itself. Summary of the invention

[0005] The purpose of an embodiment of the present invention is to provide a method for characterizing and optimizing the operating trajectory of a linear internal combustion power generation system, which can solve the problem that the existing trajectory adjustment of a linear internal combustion power generation system is mostly aimed at a single goal, that is, the thermal efficiency of the internal combustion engine, and the description of the target profile is mostly concentrated on the functional characterization of the sinusoidal profile of the virtual crankshaft, and the optimization process is complex and time-consuming. In the optimization process, there is a lack of consideration for the correlation between thermodynamics and system operating characteristics, which makes the optimization results often insignificant or difficult to implement in practical applications, and the technical problem of not truly carrying out effective and targeted trajectory optimization based on the operating characteristics of the linear internal combustion power generation system itself.

[0006] In order to solve the above-mentioned technical problems, the present invention is achieved as follows:

[0007] The embodiment of the present invention provides a method for characterizing and optimizing the operation trajectory of a linear internal combustion power generation system, comprising:

[0008] S101: selecting an optimization evaluation index from multi-dimensional evaluation indexes, wherein the multi-dimensional evaluation index includes an economic improvement index, a thermal efficiency improvement index, and a comprehensive efficiency improvement index;

[0009] S102: Obtaining mechanical constraints and basic working conditions of the linear internal combustion power generation system;

[0010] S103: according to the symmetry, derivative continuity, and derivative-derivative continuity requirements of the operation trajectory of the linear internal combustion power generation system, some decision points are used as trajectory decision points, and a B-spline thermodynamic cycle trajectory representation with the trajectory decision points as the key is designed, wherein the B-spline thermodynamic cycle trajectory representation includes three position parameters and four time parameters;

[0011] S104: using the B-spline thermodynamic cycle trajectory representation, calculating the linear internal combustion power generation system operation trajectory representation while ensuring the closure of the system operation trajectory;

[0012] S105: setting constraints of trajectory decision points and boundary conditions of multiple parameters of trajectory decision points in combination with mechanical restriction conditions, basic working conditions and the running trajectory representation of the linear internal combustion power generation system;

[0013] S106: Establishing an objective function according to the optimization evaluation index;

[0014] S107: constructing a motion trajectory to be optimized model by using a system model including in-cylinder thermal representation, system dynamics representation and electromagnetic representation, and combining the constraints of the trajectory decision point and the boundary conditions of multiple parameters of the trajectory decision point, wherein the system dynamics representation can couple the in-cylinder thermal representation and electromagnetic representation of the system according to Newton's laws of kinematics;

[0015] S108: optimizing the running trajectory model to be optimized by using a genetic algorithm and a sequential quadratic programming algorithm, and determining the optimal decision point parameters of the running trajectory model to be optimized according to the objective function;

[0016] S109: According to the optimal decision point parameters, a recursive calculation is performed using the linear internal combustion power generation system operation trajectory representation to obtain an optimal profile and calculate multiple parameter values ​​of the optimal decision point.

[0017] In an embodiment of the present invention, a method for characterizing and optimizing the operating trajectory of a linear internal combustion power generation system is proposed. According to the operating characteristics of the linear internal combustion power generation system, some decision points are used as trajectory decision points of the system, and are used as key B-spline thermodynamic cycle trajectory characterizations. Under the condition that the requirements of closure, symmetry, derivative continuity, and derivative-derivative continuity of the operating trajectory are met at the same time, the operating trajectory characterization of the linear internal combustion power generation system is calculated, which provides a basis for effectively realizing the control of the operating trajectory of the system. Furthermore, optional indicators of economic improvement index, thermal efficiency improvement index and comprehensive efficiency improvement index are provided for trajectory optimization, so as to facilitate obtaining the optimal profile of the optimal operating trajectory of the linear internal combustion power generation system from multiple angles and dimensions. The designed system model includes in-cylinder thermal characterization, system dynamics characterization, electromagnetic characterization, etc. The in-cylinder thermal characterization is coupled with the electromagnetic characterization by using the system dynamics characterization, which improves the accuracy of the system model and makes the optimization result more practical and feasible. In addition, a genetic algorithm is used in combination with a sequential quadratic programming algorithm to gradually focus on the parameters of the optimal decision point to prevent the optimization problem from falling into a local optimum. In a complete thermodynamic cycle of a linear internal combustion power generation system, the system operation characteristics are comprehensively considered and targeted regulation is carried out. The regulation process is simple, the thermal-dynamic correlation is optimized, and the final optimization effect is significant and highly feasible. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a flow chart of a method for characterizing and optimizing the operating trajectory of a linear internal combustion power generation system provided by an embodiment of the present invention.

[0019] Figure 2 It is a schematic diagram representing the operating trajectory of a linear internal combustion power generation system provided by an embodiment of the present invention.

[0020] Figure 3 This is a comparison diagram of the optimization of the operation trajectory of a linear internal combustion power generation system provided by an embodiment of the present invention.

[0021] Figure 4 It is a power comparison diagram of a linear internal combustion power generation system after the operation trajectory is optimized, provided by an embodiment of the present invention.

[0022] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In conjunction with the accompanying drawings, the following describes in detail the linear internal combustion power generation system operation trajectory characterization and optimization method provided by the embodiment of the present invention through specific embodiments and their application scenarios.

[0025] Reference Figure 1 , showing a flow chart of a method for characterizing and optimizing the operating trajectory of a linear internal combustion power generation system provided by an embodiment of the present invention.

[0026] Reference Figure 2 , showing a schematic diagram representing the operating trajectory of a linear internal combustion power generation system provided by an embodiment of the present invention.

[0027] An embodiment of the present invention provides a method for characterizing and optimizing an operation trajectory of a linear internal combustion power generation system, comprising:

[0028] S101: Selecting an optimization evaluation index from multi-dimensional evaluation indexes, wherein the multi-dimensional evaluation index includes an economic improvement index, a thermal efficiency improvement index, and a comprehensive efficiency improvement index.

[0029] It should be noted that at the beginning of the characterization and optimization method of the operating trajectory of the linear internal combustion power generation system, one or more indicators can be selected according to the ultimate optimization purpose of the linear internal combustion power generation system to be obtained in the actual application process. The selected optimization evaluation indicators will participate in the entire optimization process of the linear internal combustion power generation system, so that the final optimization result meets the various optimization evaluation indicators required in advance.

[0030] In a possible implementation manner, S101 specifically includes:

[0031] S1011: Select one or more indicators from the multi-dimensional evaluation indicators as optimization evaluation indicators.

[0032] In the embodiment of the present invention, the comprehensive efficiency improvement index is selected from the above three indexes for verification. In actual use, one or more optimization evaluation indexes can be selected to ensure that the final result meets the actual use requirements.

[0033] S102: Obtain mechanical constraints and basic working conditions of the linear internal combustion power generation system.

[0034] It can be understood that obtaining the mechanical limitations and basic working conditions of the linear internal combustion power generation system in advance is equivalent to giving the minimum requirements for the normal operation of the linear internal combustion power generation system, preventing the operating components of the linear power generation system that cannot operate normally or are damaged from participating in the system optimization process, avoiding the final optimization results from being out of touch with reality, and ensuring that the final optimization results can meet the normal operation of the system.

[0035] Among them, the mechanical limit conditions include: the maximum stroke S of the linear internal combustion power generation system without destructive working conditions and the maximum frequency T without mechanical damage. The basic working conditions include: the system cycle injection volume m f , Intake pressure P a and ignition conditions ig.

[0036] In the embodiment of the present invention, the mechanical constraints of the given linear internal combustion power generation system are as follows: the maximum stroke S = 0.03m without destructive working conditions such as cylinder collision and the maximum frequency T = 0.04s without mechanical damage to the system. The basic working conditions include: the system cycle injection volume m f =5mg, intake pressure P a =101000Pa, ignition condition ig=0.02m.

[0037] S103: According to the symmetry, derivative continuity, and derivative continuity requirements of the operation trajectory of the linear internal combustion power generation system, some decision points are used as trajectory decision points, and a B-spline thermodynamic cycle trajectory representation with the trajectory decision points as the key is designed, wherein the B-spline thermodynamic cycle trajectory representation includes three position parameters and four time parameters.

[0038] Among them, the three position parameters include: position parameter a, position parameter b and position parameter c, and the four time parameters include: time parameter t1, time parameter t2, time parameter t3 and time parameter t4. Among them, position parameter a and time parameter t1 dominate the compression process and initial compression planning of the thermal cycle of the power unit, position parameter b and time parameter t2 dominate the top dead point planning of the thermal cycle of the power unit, position parameter c and time parameter t3 dominate the expansion process planning of the thermal cycle of the power unit, and position parameter -a and time parameter t4 are used to ensure the symmetry of the thermal cycle trajectory.

[0039] S104: Using the B-spline thermodynamic cycle trajectory representation, the linear internal combustion power generation system operation trajectory representation is calculated while ensuring the closure of the system operation trajectory.

[0040] In a possible implementation, S104 specifically includes:

[0041] S1041: Based on multiple parameters characterized by the B-spline thermodynamic cycle trajectory, control nodes of the linear internal combustion power generation system are repeatedly selected to form a node matrix with a matrix size of 2×n, where n represents the number of control nodes. Each control node is described from the time and position dimensions. The control node matrix p(u) is:

[0042]

[0043] For example, to ensure the closure of the system operation trajectory, the seven parameters in the above trajectory representation are used to repeatedly select control nodes to form a control node matrix. 26 control nodes are selected, and the matrix size is 2×n, where n is the number of control nodes. In this embodiment, n=26 is taken. The control nodes are described from the time and position dimensions respectively. The control node matrix p(u) can be expressed as:

[0044]

[0045] S1042: Calculate the weight function M of each control node using the control node matrix and the Cox-de Boor recursive formula i,k (u).

[0046] S1043: Select the operation trajectory order and the intermediate node processing method, and recursively obtain the operation trajectory representation of the linear internal combustion power generation system.

[0047] Optionally, in the embodiment of the present invention, the node weight function M is calculated by controlling the node matrix and further using the Cox-de Boor recursive formula. i,k (u), the operation trajectory order is selected as 3rd order, and the intermediate node processing method is selected as quasi-uniform B-spline curve, and then the operation trajectory representation of the linear internal combustion power generation system is recursively obtained.

[0048] S105: In combination with mechanical restriction conditions, basic working conditions and the linear internal combustion power generation system operation trajectory characterization, setting constraints of the trajectory decision point and boundary conditions of multiple parameters of the trajectory decision point.

[0049] In a possible implementation manner, S105 specifically includes:

[0050] S1051: Convert the mechanical constraints to obtain the constraints of the trajectory decision point:

[0051]

[0052] Where X represents the trajectory amplitude generated recursively, S represents the maximum stroke without destructive working conditions, and T represents the maximum frequency without mechanical damage to the linear internal combustion engine system;

[0053] S1052: The boundary conditions of multiple parameters of the trajectory decision point are:

[0054]

[0055] Here, ig represents the ignition condition of the linear internal combustion power generation system.

[0056] It should be noted that by converting the mechanical constraints to obtain the constraints of the trajectory decision points, the mechanical constraints can be added to the trajectory decision point selection process in the form of parameters to make the results fit the reality, and then the boundary conditions of multiple parameters of the trajectory decision points can be obtained, so that the subsequent calculation process can be carried out under the constraints, and the results obtained are true and reliable, which is convenient for regulating the operating trajectory of the linear internal combustion engine system.

[0057] S106: Establishing an objective function according to the optimization evaluation index.

[0058] It can be understood that different objective functions are established according to different optimization evaluation indicators, various factors are incorporated into the objective function as a final solution target, and the maximum value of the objective function is solved in the form of formulas for various different indicators to obtain the optimal value of the optimization indicator.

[0059] In a possible implementation manner, S106 specifically includes:

[0060] S1061: Establish objective function based on optimization evaluation index:

[0061]

[0062] In the embodiment of the present invention, the selected objective function is the comprehensive efficiency improvement index F(p):

[0063]

[0064] S107: Utilizing a system model including in-cylinder thermal representation, system dynamics representation, and electromagnetic representation, and combining the constraints of the trajectory decision point and the boundary conditions of multiple parameters of the trajectory decision point, a motion trajectory model to be optimized is constructed, wherein the system dynamics representation can couple the in-cylinder thermal representation and electromagnetic representation of the system according to Newton's laws of kinematics.

[0065] Among them, the in-cylinder thermal characterization includes a combustion heat release module, a heat transfer module, a leakage module, a volume module, and an intake and exhaust module, and the electromagnetic characterization includes a linear motor module.

[0066] Optionally, the combustion heat release module is simulated using the Weber function, the heat transfer module is described using the Wojciech formula, the leakage module and the intake and exhaust module are described using subcritical flow and supercritical flow, wherein the Weber function includes a single Weber function, a double Weber function and a triple Weber function.

[0067] S108: Using a genetic algorithm and a sequential quadratic programming algorithm to optimize the running trajectory model to be optimized, and determining the optimal decision point parameters of the running trajectory model to be optimized according to the objective function.

[0068] It should be noted that combining the genetic algorithm (GA) and the sequential quadratic programming algorithm (SQP) for optimization can give full play to the advantages of the genetic algorithm's insensitivity to initial values ​​and strong global convergence and the sequential quadratic programming method's fast convergence speed and high precision, making up for the shortcomings of the genetic algorithm's optimization results that have random jitter and the sequential quadratic programming method's sensitivity to initial values, small convergence radius, and easy to fall into local extreme values, thereby improving the stability of the optimization process and the accuracy of the optimization results.

[0069] In the embodiment of the present invention, a genetic algorithm is used in conjunction with a sequential quadratic programming algorithm to optimize the proposed running trajectory model to be optimized. First, a global wide-net optimization is performed using a genetic algorithm, and the running trajectory is continuously optimized through iteration to clarify the optimal interval of the decision point parameters:

[0070] [abct1t2t3t4]=[0.0290.0280.0280.0050.0040.0090.024]Using the output result as the initial point, the sequential quadratic programming algorithm is used to find the optimal decision point parameters under the selected indicators of the system along the steepest descent gradient, and the objective function is searched in one dimension within the constraints until the termination criteria are met, and the optimal decision point parameters in the running trajectory to be optimized model under the current evaluation index are output. The optimization strategy of using genetic algorithm combined with sequential quadratic programming algorithm can greatly avoid the optimization from falling into local optimality.

[0071] In a possible implementation, S108 specifically includes:

[0072] S1081: A genetic algorithm is used to perform a global wide-ranging optimization search for the motion trajectory model to be optimized, and the operation trajectory of the linear internal combustion power generation system is continuously optimized iteratively to clarify the optimal ranges of multiple parameters of each trajectory decision point.

[0073] S1082: Using the optimal interval as the initial point of multiple parameters of each trajectory decision point, a sequential quadratic programming algorithm is used to find the optimal decision point parameters of the linear internal combustion power generation system and the motion trajectory to be optimized model under the optimization evaluation index along the steepest descent gradient.

[0074] S1083: Under the constraints of the trajectory decision point, a one-dimensional search is performed on the objective function until the termination criteria of the constraints of the trajectory decision point are met, and the optimal decision point parameters of the running trajectory to be optimized model under the optimization evaluation index are output.

[0075] S1084: When the number of optimization evaluation indicators is greater than 1, the Pareto optimal solution of the running trajectory model to be optimized is solved, and the Pareto optimal solution is output.

[0076] Among them, the Pareto optimality problem also refers to an ideal state of resource allocation, that is, assuming that a group of existing people and allocable resources change from one allocation state to another, at least one person becomes better off without making anyone's situation worse. This is the Pareto improvement or Pareto optimization. When selecting multiple optimization indicators, one indicator can be optimized without losing other indicators.

[0077] Reference Figure 3 , showing a comparison diagram of operation trajectory optimization of a linear internal combustion power generation system provided by an embodiment of the present invention.

[0078] Reference Figure 4 , showing a power comparison diagram of a linear internal combustion power generation system after the operation trajectory is optimized provided by an embodiment of the present invention.

[0079] exist Figure 3 and Figure 4 By comparing the optimized path with the operating trajectory curve and the power curve of the linear internal combustion power generation system without interference, it can be found that the comprehensive efficiency of the optimized path is greatly improved, which verifies the effectiveness of the present invention.

[0080] S109: According to the optimal decision point parameters, a recursive calculation is performed using the linear internal combustion power generation system operation trajectory representation to obtain an optimal profile and calculate multiple parameter values ​​of the optimal decision point.

[0081] In the embodiment of the present invention, the multiple parameters finally outputted are:

[0082] [abct1t2t3t4]=[0.02990.03000.02990.00560.00470.00940.0248]The final overall efficiency is improved by 7.01%.

[0083] In an embodiment of the present invention, a method for characterizing and optimizing the operating trajectory of a linear internal combustion power generation system is proposed. According to the operating characteristics of the linear internal combustion power generation system, some decision points are used as trajectory decision points of the system, and are used as key B-spline thermodynamic cycle trajectory characterizations. Under the condition that the requirements of closure, symmetry, derivative continuity, and derivative-derivative continuity of the operating trajectory are met at the same time, the operating trajectory characterization of the linear internal combustion power generation system is calculated, which provides a basis for effectively realizing the control of the operating trajectory of the system. Furthermore, optional indicators of economic improvement index, thermal efficiency improvement index and comprehensive efficiency improvement index are provided for trajectory optimization, so as to facilitate obtaining the optimal profile of the optimal operating trajectory of the linear internal combustion power generation system from multiple angles and dimensions. The designed system model includes in-cylinder thermal characterization, system dynamics characterization, electromagnetic characterization, etc. The in-cylinder thermal characterization is coupled with the electromagnetic characterization by using the system dynamics characterization, which improves the accuracy of the system model and makes the optimization result more practical and feasible. In addition, a genetic algorithm is used in combination with a sequential quadratic programming algorithm to gradually focus on the parameters of the optimal decision point to prevent the optimization problem from falling into a local optimum. In a complete thermodynamic cycle of a linear internal combustion power generation system, the system operation characteristics are comprehensively considered and targeted regulation is carried out. The regulation process is simple, the thermal-dynamic correlation is optimized, and the final optimization effect is significant and highly feasible.

[0084] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for characterizing and optimizing the operation trajectory of a linear internal combustion power generation system, characterized in that: include: S101: selecting an optimization evaluation index from multi-dimensional evaluation indexes, wherein the multi-dimensional evaluation indexes include an economic improvement index, a thermal efficiency improvement index, and a comprehensive efficiency improvement index; S102: Obtaining mechanical constraints and basic working conditions of the linear internal combustion power generation system; S103: according to the symmetry, derivative continuity, and derivative-derivative continuity requirements of the operation trajectory of the linear internal combustion power generation system, some decision points are used as trajectory decision points, and a B-spline thermodynamic cycle trajectory representation with the trajectory decision points as key is designed, wherein the B-spline thermodynamic cycle trajectory representation includes three position parameters and four time parameters; S104: using the B-spline thermodynamic cycle trajectory representation, calculating the linear internal combustion power generation system operation trajectory representation while ensuring the closure of the system operation trajectory; S105: setting constraints of the trajectory decision point and boundary conditions of multiple parameters of the trajectory decision point in combination with the mechanical restriction condition, the basic working condition and the running trajectory representation of the linear internal combustion power generation system; S106: Establishing an objective function according to the optimization evaluation index; S107: constructing a running trajectory optimization model by using a system model including an in-cylinder thermal representation, a system dynamics representation, and an electromagnetic representation, and combining the constraints of the trajectory decision point and the boundary conditions of multiple parameters of the trajectory decision point, wherein the system dynamics representation couples the in-cylinder thermal representation and the electromagnetic representation according to Newton's laws of kinematics; S108: optimizing the model to be optimized for the running trajectory by using a genetic algorithm and a sequential quadratic programming algorithm, and determining the optimal decision point parameters of the model to be optimized for the running trajectory according to the objective function; S109: According to the optimal decision point parameters, recursive calculation is performed using the linear internal combustion power generation system operation trajectory representation to obtain an optimal profile, and multiple parameter values ​​of the optimal decision point are calculated.

2. The linear internal combustion power generation system operation trajectory characterization and optimization method according to claim 1 is characterized in that: The S104 specifically includes: S1041: According to the multiple parameters characterized by the B-spline thermodynamic cycle trajectory, the control nodes of the linear internal combustion power generation system are repeatedly selected to form a node matrix with a matrix size of 2×n, where n represents the number of the control nodes, and each of the control nodes is described from the time and position dimensions. The control node matrix p(u) is: S1042: Calculate the weight function M of each control node using the control node matrix and the Cox-de Boor recursive formula i,k (u); S1043: selecting the operation trajectory order and the intermediate node processing method, and recursively obtaining the operation trajectory representation of the linear internal combustion power generation system; Among them, the three position parameters include: position parameter a, position parameter b and position parameter c, and the four time parameters include: time parameter t1, time parameter t2, time parameter t3 and time parameter t4, wherein the position parameter a and the time parameter t1 dominate the power unit thermal cycle compression process and the initial compression planning, the position parameter b and the time parameter t2 dominate the power unit thermal cycle top dead point planning, the position parameter c and the time parameter t3 dominate the power unit thermal cycle expansion process planning, and the position parameter -a and the time parameter t4 are used to ensure the symmetry of the thermal cycle trajectory.

3. The linear internal combustion power generation system operation trajectory characterization and optimization method according to claim 1 is characterized in that: The S105 specifically includes: S1051: Convert the mechanical constraint conditions to obtain the constraints of the trajectory decision point: Wherein, X represents the amplitude of the trajectory generated recursively, S represents the maximum stroke without destructive working conditions, and T represents the maximum frequency of the linear internal combustion power generation system without mechanical damage; S1052: The boundary conditions of the multiple parameters of the trajectory decision point are: Wherein, ig represents the ignition condition of the linear internal combustion power generation system; Among them, the three position parameters include: position parameter a, position parameter b and position parameter c, and the four time parameters include: time parameter t1, time parameter t2, time parameter t3 and time parameter t4, wherein the position parameter a and the time parameter t1 dominate the power unit thermal cycle compression process and the initial compression planning, the position parameter b and the time parameter t2 dominate the power unit thermal cycle top dead point planning, the position parameter c and the time parameter t3 dominate the power unit thermal cycle expansion process planning, and the position parameter -a and the time parameter t4 are used to ensure the symmetry of the thermal cycle trajectory.

4. The linear internal combustion power generation system operation trajectory characterization and optimization method according to claim 1 is characterized in that: The S106 is specifically as follows: S1061: Establish the objective function according to the optimization evaluation index:

5. The linear internal combustion power generation system operation trajectory characterization and optimization method according to claim 1 is characterized in that: The S108 specifically includes: S1081: using the genetic algorithm to perform global wide-net optimization on the motion trajectory model to be optimized, continuously iteratively optimizing the operation trajectory of the linear internal combustion power generation system, and clarifying the optimal intervals of multiple parameters of each trajectory decision point; S1082: using the optimal interval as the initial point of multiple parameters of each trajectory decision point, and using the sequential quadratic programming algorithm to find the optimal decision point parameters of the linear internal combustion power generation system and the motion trajectory to be optimized model under the optimization evaluation index along the steepest descent gradient; S1083: Under the constraints of the trajectory decision point, perform a one-dimensional search on the objective function until the termination criteria of the constraints of the trajectory decision point are met, and output the optimal decision point parameters of the running trajectory model to be optimized under the optimization evaluation index.

6. The linear internal combustion power generation system operation trajectory characterization and optimization method according to claim 5 is characterized in that: The S108 further includes: S1084: When the number of the optimization evaluation indicators is greater than 1, solving the Pareto optimal solution of the running trajectory model to be optimized, and outputting the Pareto optimal solution.

7. The linear internal combustion power generation system operation trajectory characterization and optimization method according to claim 1 is characterized in that: The mechanical limiting conditions include: the maximum stroke S of the linear internal combustion power generation system without destructive working conditions and the maximum frequency T without mechanical damage; the basic working conditions include: the system cycle injection volume m f , Intake pressure P a and ignition conditions ig.

8. The linear internal combustion power generation system operation trajectory characterization and optimization method according to claim 1 is characterized in that: The in-cylinder thermal characterization includes a combustion heat release module, a heat transfer module, an air leakage module, a volume module, and an intake and exhaust module, and the electromagnetic characterization includes a linear motor module.

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