A linear internal combustion power generation system combustion heat release analysis method and system

Abstract

The application discloses a linear internal combustion power generation system combustion heat release analysis method and system, and belongs to the technical field of linear internal combustion power generation systems. The method comprises the following steps: obtaining basic design and operation information of a linear internal combustion power generation system; obtaining key signals for combustion heat release analysis of the linear internal combustion power generation system under a given working condition, and pre-processing the key signals; calculating the combustion heat release rate, fuel consumption and heat release in a cycle of the linear internal combustion power generation system in a combustion heat release process; performing characteristic analysis on the combustion cycle of the linear internal combustion power generation system until the characteristic analysis is completed on all cycles; and counting combustion performance, stability and economic evaluation indexes of the linear internal combustion power generation system under the given working condition. The method provided by the application can obtain accurate and effective system combustion analysis results, and is helpful to the practical development of the linear internal combustion power generation system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of linear internal combustion power generation system, and particularly relates to a combustion and heat release analysis method and system for a linear internal combustion power generation system. BACKGROUND

[0002] The linear internal combustion power generation system is coupled by a free piston internal combustion engine and a linear motor, and through combustion, the reciprocating motion of the piston in the cylinder is driven to drive the reciprocating motion of the motor moving part, so as to realize the conversion of chemical energy into electrical energy. It has the advantages of compact structure, short energy transmission chain, flexible adjustable compression ratio, multi-fuel and reconfigurable, and has broad application potential.

[0003] Compared with the traditional internal combustion system, the linear internal combustion power generation system is free from the shackles of the crank connecting rod mechanism, and the piston has no fixed stroke limit in the motion process, can freely reciprocate within the maximum mechanical limit, and the stop point position is not fixed between cycles, which brings great convenience to the adjustment of the compression ratio and the like in the system operation.

[0004] At the same time, this "free" feature also brings trouble to the system combustion analysis. The combustion analysis of the traditional internal combustion engine usually converts the piston motion in the fixed stroke into the crank angle. On a traditional internal combustion engine with fixed structure parameters, each crank angle corresponds to a fixed piston running position, and in the combustion analysis, only the real-time crank angle obtained by using the crank speed sensor installed on the crankshaft of the internal combustion engine is input into the special combustion analyzer, and the related combustion analysis can be completed.

[0005] For the linear internal combustion power generation system, the upper and lower stop points are not fixed during operation, and for a linear internal combustion power generation system with fixed structure parameters, the fixed position of the piston during operation cannot be represented by a fixed angle or other parameters. At the same time, the piston position signal output by the linear internal combustion power generation system cannot be used as an input signal to the special combustion analyzer for the traditional internal combustion engine. Even if the signal type can be recognized, it is difficult to calculate the accurate combustion chamber volume, and the combustion analysis cannot be completed.

[0006] The combustion analysis of the linear internal combustion power generation system is the basis for system performance analysis, performance optimization and evaluation. However, there is no accurate and effective analysis method in the current technology, which restricts the practical process of the linear internal combustion power generation system. As a new type of power form with great development potential, the combustion analysis method of the linear internal combustion power generation system needs to be formed to promote the application and performance optimization of the linear internal combustion power generation system. SUMMARY

[0007] The embodiment of the present application aims to provide a linear internal combustion power generation system combustion heat release analysis method and system, which can solve the technical problem that there is no accurate and effective analysis method for the combustion heat release of the linear internal combustion power generation system, which restricts the practical process of the linear internal combustion power generation system.

[0008] In order to solve the above technical problems, the present application is implemented as follows:

[0009] The first aspect

[0010] The embodiment of the present application provides a linear internal combustion power generation system combustion heat release analysis method, comprising:

[0011] S101: obtaining basic design and operation information of the linear internal combustion power generation system;

[0012] S102: obtaining key signals for combustion heat release analysis of the linear internal combustion power generation system under a given working condition, and preprocessing the key signals;

[0013] S103: calculating the cycle combustion heat release rate, fuel consumption and heat release of the linear internal combustion power generation system in the combustion heat release process;

[0014] S104: performing feature analysis on the combustion cycle of the linear internal combustion power generation system until the feature analysis on all cycles is completed;

[0015] S105: statistically evaluating the combustion performance, stability and economy of the linear internal combustion power generation system under the given working condition.

[0016] The second aspect

[0017] The embodiment of the present application provides a linear internal combustion power generation system combustion heat release analysis system, comprising:

[0018] The basic information module is used for obtaining basic design and operation information of the linear internal combustion power generation system;

[0019] The signal acquisition module is used for obtaining key signals for combustion heat release analysis of the linear internal combustion power generation system under a given working condition, and preprocessing the key signals;

[0020] The heat release calculation module is used for calculating the cycle combustion heat release rate, fuel consumption and heat release of the linear internal combustion power generation system in the combustion heat release process;

[0021] The feature analysis module is used for performing feature analysis on the combustion cycle of the linear internal combustion power generation system until the feature analysis on all cycles is completed;

[0022] The system evaluation module is used for statistically evaluating the combustion performance, stability and economy of the linear internal combustion power generation system under the given working condition.

[0023] The present application has at least the following beneficial technical effects:

[0024] In the embodiment of the present application, the combustion performance, stability and economic evaluation index of the linear internal combustion power generation system under a given working condition can be calculated through feature calculation and heat release analysis, accurate and effective system combustion analysis results are obtained, and the practical development of the linear internal combustion power generation system is facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a flowchart of a linear internal combustion power generation system combustion heat release analysis method provided by the embodiment of the present application;

[0026] Figure 2 is a structural diagram of a linear internal combustion power generation system combustion heat release analysis system provided by the embodiment of the present application.

[0027] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the present application more clear, the technical scheme in the embodiment of the present application will be described clearly and completely below with reference to the drawings of the embodiment of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the 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 protection scope of the present application.

[0029] The linear internal combustion power generation system combustion heat release analysis method provided by the embodiment of the present application will be described in detail below with reference to the drawings and specific embodiments and application scenarios.

[0030] Embodiment one

[0031] Referring to Figure 1 , a flowchart of a linear internal combustion power generation system combustion heat release analysis method provided by the embodiment of the present application is shown.

[0032] The linear internal combustion power generation system combustion heat release analysis method provided by the embodiment of the present application comprises:

[0033] S101: Obtain the basic design and running information of the linear internal combustion power generation system.

[0034] The basic design and running information comprises: system piston area A, maximum design stroke S, irregular part mapping volume V1 of the combustion chamber, fuel type, preset ignition position ig, intake temperature T, oil injection coefficient calibration value q f , system signal sampling frequency f.

[0035] In a possible implementation, the basic design and operation information is shown in Table 1:

[0036] Table 1 Basic design and operation information table of linear internal combustion power generation system

[0037] Basic design and operating parameters Parameter value Piston area A (m 2 )]]> 2.16e-3 Maximum design stroke S (m) 7.7e-2 combustion chamber irregularities mapping volume V1 (m3) 3 ​ 6.49e-6 Fuel type (-) Gasoline Pre-set ignition position ig (m) 0.026 Intake air temperature T (K) 338 Spray coefficient calibration value g f (kg / s) 1.43 Signal sampling frequency f (Hz) 20000

[0038] S102: Obtain the key signals of the linear internal combustion power generation system under a given working condition for combustion heat release analysis, and pre-process the key signals.

[0039] The key signals include: time signal t, motor position signal x, cylinder pressure signal p, fuel injection pulse width signal h, and ignition signal g.

[0040] In a possible implementation, the pre-processing of the key signals specifically includes sub-steps S1021 to S1023:

[0041] S1021: Filter the key signals by window filtering;

[0042] S1022: Set the filter window data size w, and simultaneously eliminate abnormal signal points;

[0043] Optionally, the filter window data size w is 4.

[0044] S1023: Calculate the instantaneous cylinder volume V using the position signal after filtering and eliminating abnormal signal points, and the calculation method of the instantaneous cylinder volume V is:

[0045] V = V1 + (x + S / 2) x A

[0046] Wherein, V1 is the irregular part of the combustion chamber volume, x is the motor position signal, S is the maximum design stroke, and A is the system piston area.

[0047] S103: Calculate the cycle combustion heat release rate, fuel consumption, and heat release of the linear internal combustion power generation system during the combustion heat release process.

[0048] In a possible implementation, S103 specifically includes sub-steps S1031 to S1038:

[0049] S1031: Define the position of the compression start point as the division point of the cycle, and the signals before the compression start belong to the signals of the previous cycle, and the signals after the compression start belong to the signals of the current cycle;

[0050] S1032: Define the calculation of the combustion heat release rate and fuel consumption of the previous cycle at the beginning of the current cycle;

[0051] S1033: fitting the gas polytropic coefficient n of the linear internal combustion power generation system in the compression and expansion stages is completed

[0052]

[0053] wherein, r is the expansion or compression stage of the system, z r is the instantaneous cylinder pressure in the compression / expansion stage, y r is the instantaneous cylinder pressure at the previous time in the compression / expansion stage, x r is the ratio of the change of the cylinder volume in the compression / expansion process, x r is calculated as follows:

[0054] x r = V k / V k-1

[0055] wherein, V k-1 is the instantaneous volume at the previous time, V k is the instantaneous volume at the current time;

[0056] Optionally, the gas polytropic index n of the compression stage after fitting is 1.21, and the gas polytropic index n of the expansion stage is 1.43.

[0057] S1034: determining the estimated starting point t' of calculating the combustion heat release rate in the cycle according to the preset ignition position ig and the obtained ignition signal g start , in the case where the preset ignition position ig is consistent with the mutation position of the ignition signal g, one of them is taken as the estimated starting point; in the case where the preset ignition position ig is not consistent with the mutation position of the ignition signal g, the mutation position of the ignition signal g is taken as the estimated starting point t' start ; the last time point of the cycle is taken as the estimated end point t' end of the combustion heat release rate calculation;

[0058] S1035: in the time range of t' start to t' end , three key parameters aa, bb and cc are calculated respectively:

[0059]

[0060] bb = V k / (γ-1)

[0061] cc = (V k -V k-1 ) / 2

[0062] wherein, γ is the gas constant at the current intake temperature;

[0063] Based on the three key parameters mentioned above, the preliminary instantaneous heat release rate (HR) of the current cycle is calculated. m :

[0064] HR m =(P k -P k-1 )×aa×(bb+cc)×f / w

[0065] Among them, HR m P represents the initial instantaneous heat release rate of the current cycle. k-1 P is the cylinder pressure at the previous moment in the cycle. k This represents the current cylinder pressure.

[0066] S1036: Based on the preliminary instantaneous heat release rate, the heat release start point and heat release end point are corrected. The moment when the calculated heat release rate first exceeds zero after the estimated start point is recorded as the heat release start point t. start The moment when the last calculated heat release rate is greater than zero before the estimated end point is recorded as the heat release end point t. end , will t start To t end The instantaneous heat release rate calculated within the time range is taken as the final instantaneous heat release rate for this cycle;

[0067] S1037: Calculate the total heat release Q of this cycle based on the instantaneous heat release rate. m :

[0068]

[0069] Among them, Q m This represents the total heat released in the current cycle.

[0070] S1038: Based on the given injection coefficient calibration value q f The total fuel consumption for the current cycle is determined by the injection pulse width h. m :

[0071] fuel m =h×gf

[0072] Among them, fuel m This represents the total fuel consumption for the current cycle.

[0073] S104: Perform characteristic analysis on the combustion cycle of the linear internal combustion power generation system until the characteristic analysis of all cycles is completed.

[0074] In one possible implementation, S104 specifically includes sub-steps S1041 to S1047:

[0075] S1041: Correct the ignition point position and determine the fuel ignition delay time Δt:

[0076]

[0077] Δt = t start -t′ start

[0078] wherein, x ig is the current cycle ignition point position, Δt is the ignition delay time of the fuel;

[0079] S1042: Calculate the maximum heat release rate in the cycle according to the combustion heat release rate, and the maximum heat release rate corresponds to the piston position is:

[0080] HR max = max(HR m )

[0081]

[0082] wherein, is the time corresponding to the maximum heat release rate, is the piston position corresponding to the maximum heat release rate;

[0083] S1043: Determine the top dead center position TDC m and the bottom dead center position BDC m of the cycle:

[0084] TDC m = max(x)

[0085] BDC m = min(x)

[0086] wherein, TDC m is the top dead center position of the current cycle, and BDC m is the bottom dead center position of the current cycle;

[0087] S1044: Determine whether misfire occurs in the current cycle according to the misfire threshold of the current fuel. If the maximum heat release rate in the cycle is less than the misfire threshold of the current fuel, the cycle is determined to be a misfire cycle, and the misfire characteristic value MIS m is set to 1, and other characteristics in the S104 step are directly set to 0; if the maximum heat release rate in the cycle is greater than the misfire threshold of the current fuel, it is determined that the current cycle does not occur misfire, and the misfire characteristic value MIS m is set to 0, and S1045 is entered;

[0088] S1045: Calculate the in-cylinder peak pressure, the maximum pressure rise rate, and the piston position corresponding to the maximum pressure rise rate according to the in-cylinder pressure value.

[0089] P max = max(P)

[0090]

[0091]

[0092] wherein, is the time corresponding to the maximum pressure rise rate;

[0093] S1046: Knock judgment is performed according to the knock threshold value preset according to the fuel type, when the maximum pressure rise rate is greater than the knock threshold value, the cycle knock characteristic value KNOm is set to 1, and if the maximum pressure rise rate is less than the knock threshold value, the cycle knock characteristic value KNOm is set to 0;

[0094] S1047: The indicated work W of the current cycle is calculated according to the instantaneous cylinder volume and the in-cylinder pressure m :

[0095] W n = φPdV

[0096] wherein, W m is the indicated work of the current cycle.

[0097] S105: The combustion performance, stability and economic evaluation index of the linear internal combustion power generation system under the given working condition are counted.

[0098] In a possible implementation, S105 specifically includes sub-steps S1051 to S1055:

[0099] S1051: The total number of cycles Numb under the given working condition is counted, which can be obtained by the number of any one feature in S103, when the peak pressure is used to obtain the total number of cycles Numb, the following formula can be used:

[0100] Numb = Size(P max )

[0101] wherein, P max is the peak pressure;

[0102] S1052: The system stability is evaluated by the misfire rate Nu mis :

[0103]

[0104] wherein, MIS m is the misfire characteristic value, and sum() represents summation;

[0105] It should be noted that the system stability under the current working condition can be evaluated by the system misfire rate, and a too high misfire rate will mean that the system stability under the current working condition is low and is not suitable for long-term work.

[0106] S1053: Evaluate the combustion performance by peak cylinder pressure variation rate, top and bottom dead center variation rate, knock rate, and ignition delay average value:

[0107] Peak cylinder pressure variation rate:

[0108] wherein, is the average value of the peak cylinder pressure under the given working condition;

[0109] Top and bottom dead center variation rate:

[0110] wherein, is the average value of the top dead center under the given working condition, is the average value of the bottom dead center under the given working condition:

[0111] It should be noted that the peak cylinder pressure variation rate and the top and bottom dead center variation rate are mainly used to evaluate the combustion stability and combustion cycle variation under the current working condition of the system. The lower the peak cylinder pressure variation rate and the top and bottom dead center variation rate, the better the combustion repeatability and stability of the system under the working condition.

[0112] Knock rate:

[0113] It should be noted that the knock rate can be used to analyze the probability of knock occurrence under the current working condition to evaluate the mechanical load of the system.

[0114] Ignition delay average value for evaluating the ignition delay of the fuel under the current working condition;

[0115] S1054: Evaluate the economy of the system by fuel consumption rate:

[0116] Fuel consumption rate:

[0117] wherein, is the average value of the indicated work of the system under the given working condition, fuel m is the average value of the cycle fuel consumption, and LHV is the low heat value of the selected fuel;

[0118] S1055: Statistics of the above key evaluation indicators.

[0119] In one possible implementation, the statistics of the key evaluation indicators of the linear internal combustion power generation system under the preset working condition are shown in Table 2:

[0120] Table 2 Statistics of key evaluation indicators of linear internal combustion power generation system

[0121]

[0122] The present application has at least the following beneficial technical effects:

[0123] In the embodiment of the present application, the combustion performance, stability and economic evaluation indexes of the linear internal combustion power generation system under a given working condition can be calculated through feature calculation and heat release analysis, accurate and effective system combustion analysis results are obtained, and the practical development of the linear internal combustion power generation system is facilitated.

[0124] Embodiment two

[0125] Referring to Figure 2 , a structure schematic diagram of a linear internal combustion power generation system combustion heat release analysis system 20 provided by the embodiment of the present application is shown.

[0126] The linear internal combustion power generation system combustion heat release analysis system 20 provided by the embodiment of the present application comprises:

[0127] The basic information module 201 is used to acquire basic design and operation information of the linear internal combustion power generation system.

[0128] The signal acquisition module 202 is used to acquire key signals of the linear internal combustion power generation system under a given working condition for combustion heat release analysis, and to pre-process the key signals.

[0129] The heat release calculation module 203 is used to calculate the cycle combustion heat release rate, fuel consumption and heat release amount of the linear internal combustion power generation system in the combustion heat release process.

[0130] The feature analysis module 204 is used to perform feature analysis on the combustion cycle of the linear internal combustion power generation system until feature analysis on all cycles is completed.

[0131] The system evaluation module 205 is used to statistically acquire the combustion performance, stability and economic evaluation indexes of the linear internal combustion power generation system under a given working condition.

[0132] Optionally, the basic design and operation information comprises: system piston area A, maximum design stroke S, irregular part mapping volume V1 of the combustion chamber, fuel type, preset ignition position ig, intake temperature T, oil injection coefficient calibration value q f , system signal sampling frequency f.

[0133] Optionally, the key signals comprise: time signal t, motor position signal x, cylinder pressure signal p, oil injection pulse width signal h and ignition signal g.

[0134] Optionally, the signal acquisition module 202 is specifically used for:

[0135] Filtering the key signals through window filtering;

[0136] Setting the filtering window data size w, and synchronously eliminating abnormal signal points.

[0137] The position signal after filtering and removing abnormal signal points is used to calculate the instantaneous cylinder volume V, and the calculation method of the instantaneous cylinder volume V is as follows:

[0138] V = V1 + (x + S / 2) x A

[0139] Wherein, V1 is the irregular part of the combustion chamber volume, x is the motor position signal, S is the maximum design stroke, and A is the system piston area.

[0140] Optionally, the heat release calculation module 203 is specifically configured to:

[0141] The position of the compression start point is defined as the division point of the cycle, and the signal before the compression start belongs to the signal in the previous cycle, and the signal after the compression start belongs to the current cycle signal;

[0142] It is specified that the calculation of the combustion heat release rate and the fuel consumption is completed at the beginning of the current cycle, that is, after completing the previous cycle;

[0143] The fitting of the gas polytropic coefficient n of the linear internal combustion power generation system in the compression and expansion stages is completed:

[0144]

[0145] Wherein, r is the expansion or compression stage of the system, z r is the instantaneous cylinder pressure in the compression / expansion stage, y r is the instantaneous cylinder pressure at the previous time in the compression / expansion stage, x r is the ratio of the change of the cylinder volume in the compression / expansion process, and the calculation method of x r is as follows:

[0146] x r = V k / V k-1

[0147] Wherein, V k-1 is the instantaneous volume at the previous time, and V k is the instantaneous volume at the current time;

[0148] According to the preset ignition position ig and the obtained ignition signal g, the estimated starting point t′ start of the calculation of the combustion heat release rate in the cycle is determined, in the case that the preset ignition position ig is consistent with the mutation position of the ignition signal g, one of them is taken as the estimated starting point, in the case that the preset ignition position ig is inconsistent with the mutation position of the ignition signal g, the mutation position of the ignition signal g is taken as the estimated starting point t′ start ; and the last time point of the cycle is taken as the estimated end point t′ end of the calculation of the combustion heat release rate.

[0149] In the time range of t' start to t' end , three key parameters aa, bb and cc are calculated respectively:

[0150]

[0151] bb = V k / (γ-1)

[0152] cc = (V k -V k-1 ) / 2

[0153] wherein γ is the gas constant at the current intake temperature;

[0154] According to the above three key parameters calculation, the preliminary instantaneous heat release rate HR m of the current cycle is calculated:

[0155] HR m = (P k -P k-1 ) × aa × (bb + cc) × f / w

[0156] wherein HR m is the preliminary instantaneous heat release rate of the current cycle, P k-1 is the in-cylinder pressure at the previous time in the cycle, and P k is the in-cylinder pressure at the current time;

[0157] According to the preliminary instantaneous heat release rate, the heat release starting point and the heat release ending point are corrected, the time when the heat release rate calculation value is greater than zero for the first time after the estimated starting point is recorded as the heat release starting point t start , and the time when the last heat release rate calculation value is greater than zero before the estimated ending point is recorded as the heat release ending point t end . The instantaneous heat release rate calculation value in the time range of t start to t end is taken as the final instantaneous heat release rate of the current cycle;

[0158] According to the instantaneous heat release rate, the total heat release Q m of the cycle is calculated:

[0159]

[0160] wherein Q m is the total heat release of the current cycle;

[0161] According to the given injection coefficient calibration value q f and the injection pulse width h, the total fuel consumption fuel m of the current cycle is determined:

[0162] fuelm = h x gf

[0163] wherein fuel m is the total fuel consumption of the current cycle.

[0164] Optionally, the feature analysis module 204 is specifically configured to:

[0165] correcting the ignition point position, determining the fuel ignition delay time Δt:

[0166]

[0167] Δt = t start -t' start

[0168] wherein x ig is the ignition point position of the current cycle, and Δt is the fuel ignition delay time;

[0169] According to the combustion heat release rate, the maximum heat release rate in the cycle is calculated, and the maximum heat release rate corresponds to the piston position :

[0170] HR max = max(HR m )

[0171]

[0172] wherein, is the time corresponding to the maximum heat release rate, is the piston position corresponding to the maximum heat release rate;

[0173] determining the top dead center position TDC m and the bottom dead center position BDC m of the cycle:

[0174] TDC m = max(x)

[0175] BDC m = min(x)

[0176] wherein TDC m is the top dead center position of the current cycle, and BDC m is the bottom dead center position of the current cycle;

[0177] According to the misfire threshold of the current fuel, it is judged whether the current cycle is misfired. If the maximum heat release rate in the cycle is less than the misfire threshold of the current fuel, the cycle is judged to be a misfire cycle, and the misfire feature value MIS mis set to 1, and other features in the step S104 are directly set to 0; if the maximum heat release rate in the cycle is greater than the misfire threshold of the current fuel, it is judged that misfire does not occur in the current cycle, and the misfire feature value MIS is set to 0 m is set to 0, and S1045 is entered;

[0178] The in-cylinder peak pressure, the maximum pressure rise rate and the piston position corresponding to the maximum pressure rise rate are calculated according to the in-cylinder pressure value

[0179] P max =max(P)

[0180]

[0181]

[0182] Wherein, is the time corresponding to the maximum pressure rise rate;

[0183] The knock threshold value preset according to the fuel type is used for knock judgment, when the maximum pressure rise rate is greater than the knock threshold value, the cycle knock feature value KNOm is set to 1, and if the maximum pressure rise rate is less than the knock threshold value, the cycle knock feature value KNOm is set to 0;

[0184] The indicated work W of the current cycle is calculated according to the instantaneous in-cylinder volume and the in-cylinder pressure m :

[0185] W m =φPdV

[0186] Wherein, W m is the indicated work of the current cycle.

[0187] Optionally, the system evaluation module 205 is specifically configured to:

[0188] The total number of cycles Numb under the given working condition is counted, the total number of cycles Numb can be obtained by the number of any one feature in S103, when the peak pressure is used to obtain the total number of cycles Numb, the following formula can be used:

[0189] Numb=Size(P max )

[0190] Wherein, P max is the peak pressure;

[0191] The system stability is evaluated by the misfire rate Nu mis :

[0192]

[0193] Wherein, MIS mis the misfire characteristic value, sum() represents summation;

[0194] The combustion performance is evaluated by the peak cylinder pressure variation rate, the top and bottom dead center variation rate, the knock rate, and the ignition delay average value:

[0195] The peak cylinder pressure variation rate is:

[0196] wherein, is the average value of the peak cylinder pressure under a given working condition;

[0197] The top and bottom dead center variation rate is:

[0198] wherein, is the average value of the top dead center under a given working condition, is the average value of the bottom dead center under a given working condition;

[0199] The knock rate is:

[0200] The ignition delay average value is used for evaluating the ignition delay of the fuel under the current working condition;

[0201] The economy of the system is evaluated by the fuel consumption rate:

[0202] The fuel consumption rate is:

[0203] wherein, is the average value of the indicated work of the system cycle under a given working condition, fuel m is the average value of the cycle fuel consumption, and LHV is the low heat value of the selected fuel;

[0204] The above key evaluation indexes are counted.

[0205] The linear internal combustion power generation system combustion heat release analysis system 20 provided by the present application can realize the processes realized in the above method embodiments, and thus will not be repeated here.

[0206] The virtual system provided by the present application can be a system, or a component, an integrated circuit, or a chip in a terminal.

[0207] The present application has at least the following beneficial technical effects:

[0208] In the embodiments of the present application, the combustion performance, stability and economy evaluation indexes of the linear internal combustion power generation system under a given working condition can be counted through feature calculation and heat release analysis, accurate and effective system combustion analysis results can be obtained, and the practical development of the linear internal combustion power generation system is facilitated.

[0209] The above merely illustrates the embodiments of the present application, and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. within the spirit and principles of the present application should be included in the scope of the claims of the present application.

Claims

1. A linear internal combustion power generation system combustion heat release analysis method characterized by, The method comprises the following steps: S101: obtaining basic design and operation information of the linear internal combustion power generation system; S102: obtaining key signals of the linear internal combustion power generation system under a given working condition for combustion heat release analysis, and preprocessing the key signals; S103: calculating combustion heat release rate, fuel consumption and heat release of each cycle in the combustion heat release process of the linear internal combustion power generation system; S104: performing characteristic analysis on the combustion cycle of the linear internal combustion power generation system until the characteristic analysis on all cycles is completed; S105: statistically evaluating the combustion performance, stability and economy of the linear internal combustion power generation system under the given working condition; The preprocessing of the key signals specifically comprises the following steps: S1021: filtering the key signals through window filtering; S1022: setting the filter window data size w and synchronously eliminating abnormal signal points; S1023: calculating the instantaneous cylinder volume V by using the position signal after filtering and eliminating the abnormal signal points, and the calculation method of the instantaneous cylinder volume V is as follows: ; Wherein, V1 is the irregular part of the combustion chamber, x is the motor position signal, S is the maximum design stroke, and A is the system piston area; The S103 specifically comprises the following steps: S1031: defining the position of the compression starting point as the division point of the cycle, and the signals before the compression start belong to the signals in the previous cycle, and the signals after the compression start belong to the signals in the current cycle; S1032: defining the calculation of the combustion heat release rate and fuel consumption at the beginning of the current cycle, i.e. the completion of the combustion heat release rate and fuel consumption of the previous cycle; S1033: completing the fitting of the gas polytropic coefficient n of the linear internal combustion power generation system in the compression and expansion stages: ; where r is the ratio of the volume change during the expansion or compression phase of the system, z r is the instantaneous cylinder pressure during the compression / expansion phase, y r is the instantaneous cylinder pressure at the previous time during the compression / expansion phase, x r is the ratio of the volume change during the compression / expansion process of the system, x r is calculated as: ; V k-1 V k V S1034: determining a predicted starting point for calculating the combustion heat release rate in the cycle according to the preset ignition position ig and the obtained ignition signal g , in the case where the preset ignition position ig is consistent with the mutation position of the ignition signal g, taking one of them as the predicted starting point; in the case where the preset ignition position ig is not consistent with the mutation position of the ignition signal g, taking the mutation position of the ignition signal g as the predicted starting point ; taking the last time point of the cycle as a predicted end point for calculating the combustion heat release rate ; S1035: In to the time range, respectively, three key parameters aa, bb and cc are calculated: ; ; ; Wherein, γ is the gas constant at the current intake temperature; Based on the calculation of the three key parameters, calculate the preliminary instantaneous heat release rate HR for the current cycle m : ; wherein HR m is the preliminary instantaneous heat release rate of the current cycle, P k-1 is the in-cylinder pressure at the previous time in the cycle, P k is the in-cylinder pressure at the current time, and f denotes the signal sampling frequency. S1036: Correcting the exothermic starting point and the exothermic ending point according to the preliminary instantaneous exothermic rate, taking the time when the calculated value of the exothermic rate is greater than zero for the first time after the estimated starting point as the exothermic starting point and taking the time when the last calculated value of the exothermic rate is greater than zero before the estimated ending point as the exothermic ending point the calculated value of the instantaneous exothermic rate at the time point of the exothermic starting point as the initial value of the instantaneous exothermic rate at the exothermic starting point the calculated value of the instantaneous exothermic rate at the time point of the exothermic ending point as the final value of the instantaneous exothermic rate at the exothermic ending point the calculated value of the instantaneous exothermic rate within the time range of the exothermic starting point to the exothermic ending point as the final instantaneous exothermic rate of the current cycle; S1037: Calculate the total heat release Q of the cycle according to the instantaneous heat release rate m : ; where Q m is the total heat release of the current cycle; S1038: Determine the total fuel consumption of the current cycle according to the given injection coefficient calibration value q f and the injection pulse width h : ; wherein, is the total fuel consumption for the current cycle.

2. The linear internal combustion generator system combustion heat release analysis method according to claim 1, characterized by, The basic design and operation information includes: system piston area A, maximum design stroke S, combustion chamber irregular part mapping volume V1, fuel type, preset ignition position ig, intake temperature T, fuel injection coefficient calibration value q f , system signal sampling frequency f.

3. The linear internal combustion generator system combustion heat release analysis method according to claim 1, characterized by, The key signals include: a time signal t, a motor position signal , a cylinder pressure signal p, an injection pulse width signal h, and an ignition signal g.

4. The linear internal combustion generator system combustion heat release analysis method of claim 1, wherein, The S104 specifically comprises the following steps: S1041: Correcting the ignition point position, determining the fuel ignition delay time : ; ; wherein x ig is the current cycle ignition point position, is the fuel ignition delay time; S1042: Calculate the maximum heat release rate in the cycle from the heat release rate, the maximum heat release rate corresponding to the piston position is: ; ; wherein, is the time at which the maximum heat release rate occurs, is the piston position at which the maximum heat release rate occurs; S1043: Determine the top dead center position TDC of the cycle m , the bottom dead center position BDC m : ; ; where TDC m is the top dead center position of the current cycle, BDC m is the bottom dead center position of the current cycle; S1044: judging whether misfire occurs in the current cycle according to the misfire threshold of the current fuel, if the maximum heat release rate in the cycle is less than the misfire threshold of the current fuel, the cycle is judged as a misfire cycle, and the misfire feature value MIS m is set as 1, and other features in the S104 step are directly set as 0; if the maximum heat release rate in the cycle is greater than the misfire threshold of the current fuel, it is judged that misfire does not occur in the current cycle, and the misfire feature value MIS m is set as 0, and S1045 is entered; S1045: Calculate the in-cylinder peak pressure, the maximum pressure rise rate, and the piston position corresponding to the maximum pressure rise rate according to the in-cylinder pressure value : ; ; ; wherein, is the time instant corresponding to the maximum pressure rise rate; S1046: judging the knock according to the knock threshold value preset according to the fuel type, setting the cycle knock characteristic value KNOm as 1 when the maximum pressure rise rate is greater than the knock threshold value, and setting the cycle knock characteristic value KNOm as 0 when the maximum pressure rise rate is less than the knock threshold value; S1047: Calculate indicated work W of the current cycle based on the instantaneous cylinder volume and the in-cylinder pressure m : ; where W m is the indicated work for the current cycle.

5. The linear internal combustion generator system combustion heat release analysis method according to claim 4, characterized by, The S105 specifically comprises the following steps: S1051: statistically obtaining the total number Numb of cycles under the given working condition, which can be obtained by the number of any one characteristic in S103, and when the peak pressure is used to obtain the total number Numb of cycles, the following formula can be used: ; wherein Ppeak is the peak pressure; S1052: by misfire rate Evaluation of system stability: ; wherein is the misfire characteristic value, sum() denotes the summation; S1053: evaluating the combustion performance by the peak cylinder pressure variation rate, top and bottom dead center variation rate, knock rate and average ignition delay: The peak cylinder pressure variation rate: ; wherein is the average value of the peak cylinder pressure at the given operating condition; the upper and lower dead center variation rate: ; wherein is the average value of the top dead center in the given operating condition, is the average value of the bottom dead center in the given operating condition; the knock ratio: ; the average value of the ignition delay for evaluating the ignition delay using the fuel in the current operating condition; S1054: evaluating the economy of the system by the fuel consumption rate: The fuel consumption rate: ; wherein, is the average value of the indicated work of the system cycle for the given operating condition, is the average value of the specific fuel consumption of the cycle, and LHV is the lower heating value of the selected fuel. S1055: statistically obtaining the above key evaluation indexes.

6. A linear internal combustion engine generator system combustion heat release analysis system for realizing a linear internal combustion engine generator system combustion heat release analysis method according to claims 1 to 5, characterized by, The method comprises the following steps: A basic information module is used to obtain the basic design and operation information of the linear internal combustion power generation system; A signal acquisition module is used to obtain the key signals of the linear internal combustion power generation system under a given working condition for combustion heat release analysis, and to preprocess the key signals; A heat release calculation module is used to calculate the combustion heat release rate, fuel consumption and heat release of each cycle in the combustion heat release process of the linear internal combustion power generation system; a characteristic analysis module, configured to perform characteristic analysis on the combustion cycle of the linear internal combustion power generation system until the characteristic analysis is completed for all cycles; a system evaluation module, configured to statistically evaluate the combustion performance, stability and economy of the linear internal combustion power generation system under the given working condition.

7. The linear internal combustion generator system combustion heat release analysis system of claim 6, wherein, The basic design and operation information includes: system piston area A, maximum design stroke S, combustion chamber irregular part mapping volume V1, fuel type, preset ignition position ig, intake temperature T, fuel injection coefficient calibration value q f , system signal sampling frequency f.

8. The linear combustion power generation system combustion heat release analysis system according to claim 6, characterized by, The key signals include: a time signal t, a motor position signal , a cylinder pressure signal p, an injection pulse width signal h, and an ignition signal g.

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