A parameter matching method for quasi-dimensional combustion model of high-speed diesel engines

Abstract

The present invention discloses a method for matching parameters of a quasi-dimensional combustion model of a high-speed diesel engine, and belongs to the technical field of internal combustion engines. The method comprises: S1, judging whether there is an obvious afterburning phenomenon caused by abnormal fuel injection during the diesel engine test; if so, proceeding to the next step, otherwise, ending the matching; S2, constructing an in-cylinder combustion model, performing in-cylinder process verification and whole machine parameter verification, and if there are abnormalities in the heat release rate and the exhaust temperature before and after the turbine, proceeding to the next step, otherwise, ending the matching; S3, changing the injection mode from pre-injection and main injection to main injection and post-injection, and determining the main injection parameters and post-injection parameters; S4, obtaining simulation data; S5, comparing simulation data with test data; when the comparison result meets the requirements, the construction of the in-cylinder combustion model based on post-injection is completed, otherwise, the main injection and post-injection parameters are readjusted and returned to S4. The present invention can realize accurate simulation of the combustion process when post-injection exists through a quasi-dimensional combustion model.

Description

Technical Field

[0001] The invention belongs to the technical field of internal combustion engines, and in particular relates to a method for matching parameters of a quasi-dimensional combustion model of a high-speed diesel engine. Background Art

[0002] As the main power electromechanical equipment of many equipment, diesel engines provide powerful mechanical power for the efficient operation of equipment. The strength of their operating index output determines the specific performance of the equipment in various aspects. However, the performance of diesel engines is often closely related to the structural parameters, material ratio, fuel selection, etc. of the diesel engine design. Changes in these parameters force the economy, power and reliability of the diesel engine to change. Therefore, it is very important to optimize the parameters in the diesel engine design process. In the research and development stage of diesel engines, diesel engine whole machine tests are often carried out to clarify the parameters of diesel engines and evaluate the performance of diesel engines. However, when the fuel injection system and the combustion chamber are poorly matched, there is a large oil beam hitting the wall in the diesel engine whole machine test, which causes serious afterburning, and even fuel combustion in the exhaust stroke. When the above situation occurs, various combustion simulation methods in GT-POWER cannot simulate the combustion process normally.

[0003] At present, most of the methods to solve this problem use 3D simulation software to match the injection system with the combustion chamber. However, the 3D simulation model is not conducive to the subsequent simulation analysis of the performance of the diesel engine as a whole, and cannot be used to check and optimize the diesel engine as a whole, and the intuitiveness is poor. Most of the abnormal fuel injection diagnosis methods are based on empirical models or large data models, which requires multiple tests on diesel engines, and it is difficult to obtain abnormal fuel injection data. Therefore, the abnormal fuel injection diagnosis methods based on empirical models and data models will greatly increase the R&D cost. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the above-mentioned related art at least to a certain extent.

[0005] To this end, the purpose of the present invention is to provide a quasi-dimensional combustion model parameter matching method for a high-speed diesel engine, which can accurately simulate the serious afterburning in the cylinder or even the exhaust duct combustion process caused by abnormal fuel injection through quasi-dimensional combustion model parameter matching.

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

[0007] An embodiment of the present invention provides a method for matching parameters of a quasi-dimensional combustion model of a high-speed diesel engine, the method comprising:

[0008] S1. Determine whether there is obvious afterburning phenomenon caused by abnormal fuel injection during the diesel engine test; if so, proceed to the next step, otherwise, end the matching; the obvious afterburning phenomenon is cylinder afterburning, exhaust port combustion or both;

[0009] S2. Set the model injection parameters according to the test injection law, build the in-cylinder combustion model, and perform calibration based on the test cylinder pressure curve and heat release rate curve. After the in-cylinder process calibration is completed, perform the whole machine parameter calibration to determine whether there are abnormalities in the heat release rate and the exhaust temperature before and after the turbine. If yes, proceed to the next step, otherwise, terminate the matching;

[0010] S3, changing the injection mode of the in-cylinder combustion model from pre-injection and main injection to main injection and post-injection, wherein the main injection parameters after the change are consistent with the main injection parameters before the change; determining the post-injection parameters according to the main injection parameters;

[0011] S4, using the in-cylinder combustion model obtained in S3 to perform simulation and obtain simulation data;

[0012] S5. Compare the simulated cylinder pressure data with the experimental cylinder pressure data, the simulated heat release rate curve with the experimental heat release rate curve, and the simulated explosion pressure value with the experimental explosion pressure value; if the comparison result meets the requirements, the construction of the cylinder combustion model based on afterburning is completed, otherwise readjust the main injection and after-injection parameters and return to S4.

[0013] In addition, the high-speed diesel engine quasi-dimensional combustion model parameter matching method according to the present invention may also have the following additional technical features:

[0014] In some embodiments, the content of determining whether there is obvious afterburning during the diesel engine test includes:

[0015] Construct an in-cylinder combustion model and adjust the corresponding combustion parameters of the model according to the test data, including pre-injection and main injection parameters;

[0016] Check cylinder pressure and heat release rate curves;

[0017] Conduct model combustion simulation;

[0018] Compare the simulated exhaust temperature parameters with the experimental exhaust temperature parameters; determine whether there is obvious afterburning based on the size relationship and difference between the two.

[0019] In some embodiments, when the simulated exhaust temperature parameter is lower than the tested exhaust temperature parameter and the difference between the two is greater than a first judgment threshold, it is determined that there is an obvious afterburning phenomenon, otherwise there is no obvious afterburning phenomenon.

[0020] In some embodiments, the main spray parameters in step S3 include:

[0021] The main injection timing is determined based on the starting point of the test heat release rate;

[0022] The main injection pulse width is determined according to the test ECU test;

[0023] The main injection amount is determined according to the circulating oil amount;

[0024] The main injection rate is determined by the circulating oil volume and pulse width.

[0025] In some embodiments, the contents of determining the post-spray parameters according to the main spray parameters in step S3 and re-adjusting the post-spray parameters in step S4 both include:

[0026] Reduce the main injection amount as the post injection amount;

[0027] The end time of main injection is taken as the timing of post-injection;

[0028] The post-injection pulse width is determined based on the diesel engine's afterburning degree and experience;

[0029] The post-injection rate is determined by the post-injection fuel quantity and the post-injection pulse width.

[0030] In some of the embodiments, the nozzle hole diameter and the number of nozzle holes remain unchanged when the main spray and post-spray parameters are readjusted.

[0031] In some embodiments, the content of determining the post-spray parameters according to the main spray parameters in step S3 includes:

[0032] The main injection amount is reduced to simulate the initial combustion rate reduction caused by the injection fuel beam hitting the wall. In order to ensure that the circulating oil volume remains unchanged, the reduced main injection amount is used as the post-injection amount for the second injection.

[0033] The end time of main injection is taken as the timing of post-injection;

[0034] The post-spray pulse width is determined based on the degree of agreement between the heat release rate curve of the model simulation and the heat release rate curve of the test;

[0035] The post-injection rate is determined by the post-injection fuel quantity and the post-injection pulse width.

[0036] In some embodiments, the method for matching parameters of a high-speed diesel engine quasi-dimensional combustion model further includes the following steps before step S1:

[0037] S001. Build the GT-POWER diesel engine model, including the fuel injection system model;

[0038] S002. Adjust the injection timing, injection pulse width and injector structural parameters of the model according to the test data.

[0039] In some embodiments, the method for matching parameters of a high-speed diesel engine quasi-dimensional combustion model further includes the following steps after step S5:

[0040] S003. Adjust the entrainment coefficient, ignition delay coefficient, premixed combustion rate coefficient and diffusion combustion rate coefficient of the in-cylinder combustion model according to the test data;

[0041] S004. Check the simulated cylinder pressure curve and the test cylinder pressure curve, and check the simulated heat release rate curve and the test heat release rate.

[0042] An embodiment of the present invention also provides a high-speed diesel engine quasi-dimensional combustion model parameter matching device, including a memory and a processor, wherein the memory stores a program, and when the processor runs the program, it can implement the content of the high-speed diesel engine quasi-dimensional combustion model parameter matching method as described in any of the above items.

[0043] Compared with the prior art, the present invention has at least the following beneficial effects:

[0044] In the embodiment of the present invention, the provided high-speed diesel engine quasi-dimensional combustion model parameter matching method can construct a cylinder combustion model to well simulate the combustion process of the diesel engine with obvious afterburning by modifying the cylinder combustion model and adjusting the injection parameters, thereby solving the problem that the existing GT-POWER combustion simulation method cannot normally simulate the combustion process with afterburning.

[0045] In an embodiment of the present invention, a high-speed diesel engine quasi-dimensional combustion model parameter matching method is provided, which can accurately simulate the combustion process in the presence of afterburning through a quasi-dimensional combustion model by modifying the in-cylinder combustion model and a unique injection parameter adjustment method, thereby avoiding the use of a three-dimensional simulation model, and solving the problem that three-dimensional simulation software cannot be used for the calibration and optimization of the entire diesel engine and has poor intuitiveness.

[0046] The high-speed diesel engine quasi-dimensional combustion model parameter matching device of the present invention includes the high-speed diesel engine quasi-dimensional combustion model parameter matching method, and thus at least has all the features and advantages of the high-speed diesel engine quasi-dimensional combustion model parameter matching method, which will not be repeated here. Additional aspects and advantages of the present invention will be partially given in the following description, and part will become obvious from the following description, or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A flow chart of a method for matching parameters of a quasi-dimensional combustion model of a high-speed diesel engine disclosed in one embodiment of the present invention;

[0048] Figure 2A calibration result diagram of the cylinder pressure and heat release rate of the in-cylinder combustion model modeled by the DIPulse combustion model disclosed in one embodiment of the present invention;

[0049] Figure 3 Establishing a quasi-dimensional combustion process diagram for a DIPulse combustion model before modified fuel injection disclosed in one embodiment of the present invention;

[0050] Figure 4 Establishing a quasi-dimensional combustion process diagram for a DIPulse combustion model after modified fuel injection disclosed in one embodiment of the present invention;

[0051] Figure 5 A diagram showing the cylinder pressure and heat release rate verification results of an in-cylinder combustion model for correcting injection parameters disclosed in one embodiment of the present invention. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of 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.

[0053] The embodiments of the present invention are described in detail below through specific embodiments and application scenarios in conjunction with the accompanying drawings.

[0054] In some embodiments of the present invention, a method for matching parameters of a quasi-dimensional combustion model of a high-speed diesel engine is provided.

[0055] In some embodiments of the present invention, a high-speed diesel engine is modeled as a whole: based on the test data of a physical diesel engine, the diesel engine is modeled based on the GT-POWER software. The DIPulse combustion model in GT-POWER is selected. The DIPulse combustion model is a predictive combustion model designed specifically for direct injection diesel engines. The combustion model can accurately simulate the injection rate curves of different injectors and can take into account the influence of injection pressure, number and diameter of spray holes.

[0056] Modeling of the injector of the high-speed diesel engine: Select the InjMultiProfileConn injector model in GT-POWER. This model can establish a multi-stage injection process. By adjusting the parameter model such as the cyclic injection amount, injection timing, injection pulse width, injection rate, number of single injector holes and injection hole diameter, different injection processes can be simulated. Combined with the setting of the combustion parameters of the DIPulse combustion model, the combustion process of different high-speed diesel engines with different injectors can be simulated, and the influence of different injectors on the overall performance of the high-speed diesel engine can be compared and analyzed.

[0057] Adjust the combustion parameters of the DIpulse combustion model: adjust the Entrainment Rate Multiplier (entrainment coefficient), Ignition Delay Multiplier (ignition delay coefficient), Premixed Combustion Rate Multiplier (premixed combustion rate coefficient), Diffusion Combustion Rate Multiplier (diffusion combustion rate coefficient) in the DIpulse combustion model, and use the high-speed diesel engine test cylinder pressure and heat release rate data as a reference to adjust the above parameters, calibrate the model simulation cylinder pressure and heat release rate curves to ensure consistency with the test data. After completing the above process, it is considered that the in-cylinder combustion process has been calibrated. Within the allowable error range, there may be different combinations of combustion parameters when the simulation cylinder pressure curve and the test cylinder pressure curve are calibrated. Therefore, the problem to be solved by this method is how to adjust the combustion parameters of the DIPulse combustion model according to the whole machine test data to ensure that the model reduces the error to the greatest extent and ensure the authenticity of the model simulation data. Based on this, the performance of the high-speed diesel engine injector is optimized to improve the performance of the high-speed diesel engine as a whole.

[0058] Cylinder pressure calibration process: The common calibration method for GT-POWER internal combustion engines is to calibrate a series of parameters such as the intake and exhaust system, the injection system, and the supercharging system, and then start adjusting the parameters of the combustion process in the cylinder, calibrate the simulation and test cylinder pressure curves, and after the calibration is completed, the model is considered to be authentic. However, during the diesel engine test, the actual performance of the whole machine is affected by the environment, and there will be inevitable delays in its own electronic control system, such as delays in the electronic injection system. Affected by the above factors, various unpredictable situations will occur during the test. Only calibrating the cylinder pressure curve cannot guarantee that the model can fully reflect various situations during the test of the whole high-speed diesel engine. Based on this problem, the present invention conducts a high-speed diesel engine model calibration study based on a quasi-dimensional combustion model, and based on this, conducts a high-speed diesel engine performance optimization method study. For the method flow, please refer to Figure 1 As shown, the steps include:

[0059] Step 1: Model the GT-POWER diesel engine.

[0060] Step 2: Model the fuel injection system to obtain a fuel injection system model;

[0061] The parameters related to the injection system model have an important influence on the model simulation results. This model can be used to compare the effects of different injector structures on the combustion process. The injection rate is calibrated by the injection rate curve measured by the test, and the injection pulse width is determined by the time when the integral value of the injector mass flow curve reaches the circulating oil volume. The injection timing is adjusted according to the main injection timing value provided by the test data to ensure that the simulated cylinder pressure and heat release rate phase are consistent with the test measured values.

[0062] Step 3: Parameter adjustment, including adjustment of injection timing, injection pulse width and injector structure parameters;

[0063] Step 4: Construct the in-cylinder combustion process based on the DIPulse combustion model to obtain the in-cylinder combustion model;

[0064] Step 5: Adjust parameters, including adjusting the entrainment coefficient, ignition delay coefficient, premixed combustion rate coefficient, and diffusion combustion rate coefficient;

[0065] Step 6: Verify simulation data and test data, including cylinder pressure curve verification and heat release rate curve verification;

[0066] More specifically, it includes timing verification, trend verification and numerical verification.

[0067] The DIPulse combustion model is used to model the cylinder pressure and heat release rate of the in-cylinder combustion. Figure 2 The simulated exhaust temperature before the turbine is much lower than the experimental exhaust temperature.

[0068] In view of the conclusions drawn from the above heat release rate modeling method: 1) There is an obvious early stage phenomenon in the experimental heat release rate; 2) Compared with other in-cylinder combustion modeling methods, the DIPulse combustion model has a certain degree of in-cylinder afterburning phenomenon. When the DIpulse combustion model is used to model in-cylinder combustion, the experimental heat release rate is significantly lower than the simulated heat release rate curve, but the simulated exhaust temperature is lower than the experimental exhaust temperature, which is contrary to the theory. Therefore, it is speculated that the extreme exhaust port combustion condition is caused by abnormal fuel injection.

[0069] For the above reasons, none of the above models can accurately simulate the obvious afterburning phenomenon of diesel engines equipped with injectors, and the heat release rate curve measured in the test has problems of early truncation and too low peak value. Moreover, the injection rate of the model is set with reference to the injector mass flow curve, and the injection pulse width obtained is too long compared with the main control pulse width calibrated by the ECU.

[0070] Determine whether the combustion process simulated by the constructed DIPulse combustion model has obvious afterburning caused by abnormal fuel injection. For the determination method, please refer to Figure 3 As shown, the steps include:

[0071] Step 1: For the constructed DIPulse combustion model, keep the pre-injection and main injection parameters of the test injection process unchanged;

[0072] Step 2: Adjust the combustion parameters and calibrate the simulation and test parameters, including cylinder pressure and heat release rate curves;

[0073] After the parameters of other engine components are set according to the test parameters, the in-cylinder combustion parameters, i.e. the parameters of the DIpulse combustion model, are adjusted to calibrate the cylinder pressure and heat release rate curve. The combustion parameters adjusted are mainly the four parameters introduced above, such as Entrainment rateMultiplier;

[0074] Step 3: After the cylinder pressure and heat release rate curves are verified, the exhaust temperature parameters of the simulation and the test are compared;

[0075] Determine whether there is a large deviation between the exhaust temperature parameters of the simulation and the test, and whether the simulation parameters are significantly lower than the test parameters;

[0076] Step 4: Based on the judgment result of step 3, determine whether there is obvious afterburning phenomenon during the diesel engine test; when the simulated exhaust temperature parameter is lower than the test exhaust temperature parameter and the difference between the two is large enough (greater than the preset first judgment threshold), it is determined that there is obvious afterburning phenomenon.

[0077] When there is a significant phenomenon of afterburning, it is necessary to readjust the settings of injection-related parameters. Based on the obvious phenomenon of diesel engine afterburning, adjust the injection amount, injection pulse width and injection timing of the pre-injection and main injection. Due to the difference in injection pulse width caused by the opening delay of the electronic control system and the different injection rail pressures at the speed operating point, it is impossible to refer to the actual measured value of the injection rate of the injector to accurately determine the parameters that need to be set in the model, that is, the accurate calculation of the injection timing and injection pulse width. Therefore, the injection parameters are set as follows:

[0078] 1) In order to simulate the phenomenon of large combustion delay, the original two injections (pre-injection and main injection) are changed to main injection and post-injection (that is, the original pre-injection is cancelled, the main injection parameters are retained, and post-injection is set in the expansion stroke and exhaust stroke to simulate severe afterburning phenomenon);

[0079] 2) The main injection timing is determined by the starting point of the heat release rate of the main injection section in the test heat release rate curve. The starting point of the main injection heat release rate is used as the main injection timing. The main injection pulse width is determined by the main injection pulse width measured in the test. The main injection amount is initially determined as the circulating oil amount of the pre-injection and the main injection. The injection rate of the main injection is also determined by the area of ​​the injection rate integral curve as the circulating oil amount. According to the above calculation method, the injection rate is considered to be a constant value, and the integral area is a rectangle. The length of the rectangle is the main injection pulse width, and the height of the rectangle is the injection rate of the main injection. All parameters of the initial main injection can be determined;

[0080] 3) Based on the DIPulse combustion model mentioned above, the combustion parameters are adjusted. Since the explosion pressure value of the current injection rate increase will be higher than the experimental data, the main injection amount is reduced to simulate the initial combustion rate reduction caused by the injection oil beam hitting the wall. In order to ensure that the circulating oil volume remains unchanged, the reduced main injection amount is used as the post-injection amount for the second injection;

[0081] 4) The amount of post-injection fuel can be obtained from 3). The post-injection timing is set to start after the main injection ends, that is, it is determined by the main injection pulse width. The crankshaft rotation angle corresponding to the main injection pulse width is calculated according to different speeds, and the post-injection timing is obtained by adding it to the main injection timing. The post-injection pulse width can be adjusted according to the degree of agreement between the model simulation heat release rate curve and the experimental heat release rate curve; due to the obvious afterburning of the diesel engine, the post-injection pulse width of 2ms is used as the basis for adjustment;

[0082] 5) Repeat the adjustments from 2) to 4) above until the simulated cylinder pressure and heat release rate curves are basically consistent with the test cylinder pressure and heat release rate curves.

[0083] After correcting the injection parameters, the DIPulse combustion model is used again to establish the in-cylinder combustion model. The diameter and number of the injector holes remain unchanged, and the injection timing, injection pulse width, and injection rate parameters are changed to perform model simulation to simulate the phenomenon of obvious diesel engine afterburning and high exhaust temperature. Figure 4 As shown, the steps include:

[0084] Step 1: Establish an in-cylinder combustion model based on the DIPulse combustion model;

[0085] Step 2: Change the pre-spray + main spray mode to the main spray + post-spray mode, and keep the main spray parameters in the original pre-spray + main spray mode;

[0086] Among them, the main injection timing is determined by the starting point of the test heat release rate, the main injection pulse width is obtained by the test ECU test, the main injection amount is initially determined as the circulating oil amount, and the main injection rate is obtained by dividing the circulating oil amount by the pulse width;

[0087] The post-injection parameters here are mainly determined by the pre-injection parameters during the test. The post-injection circulation oil volume is greater than or equal to the pre-injection oil volume, and the post-injection pulse width is defined as 2ms. The basis is as follows: because the injector design and the combustion chamber are not well matched in the test, the combustion has obvious afterburning phenomenon, and the test shows a higher pre-turbulent exhaust temperature. The GT simulation parameters are set according to the test injection law. Since the simulation is an idealized situation, it is impossible to simulate the serious problem of afterburning, resulting in the simulated exhaust temperature being much lower than the test exhaust temperature. Therefore, the test pre-injection is used as the simulated post-injection, and the initial defined post-injection oil volume is the test pre-injection oil volume, and the injection pulse width is 2ms, slowing down the post-injection rate to simulate the serious problem of afterburning. If the cylinder pressure curve is checked within the allowable error range at this time, and the simulated exhaust temperature is still low, the main injection amount is slightly reduced, the post-injection amount is increased, and the total circulation oil volume remains unchanged. The post-injection amount is within the range of 5%~7% of the total circulation oil volume.

[0088] Step 3: Compare the cylinder pressure curves of simulation and test. If the simulation explosion pressure value exceeds the test explosion pressure value, readjust the parameters of the main injection and post-injection.

[0089] The specific adjustments include: reducing the main injection amount as the post-injection amount, the post-injection timing is the end time of the main injection, the post-injection pulse width is selected as 2ms to simulate the afterburning, and the post-injection rate is obtained by dividing the post-injection amount by the pulse width;

[0090] Step 4: Compare the cylinder pressure and heat release rate curves of the simulation and the test to determine whether the simulation explosion pressure value exceeds the test explosion pressure value; if it exceeds, return to step 3 to readjust the parameters of the main injection and post-injection; otherwise, proceed to the next step;

[0091] Step 5: Compare the simulation and test machine parameters; if the comparison result is within the preset range, the matching is completed, otherwise re-match. The re-matching mainly adjusts the circulating oil distribution ratio of the main injection and the post-injection. If the simulated exhaust temperature is still low after the cylinder pressure curve is calibrated, it means that the afterburning phenomenon in the test process has not been simulated; at this time, reduce the circulating oil volume of the main injection and increase the circulating oil volume of the post-injection to ensure that the total circulating oil volume remains unchanged; the injection pulse width is no longer adjusted; after the injection parameters are adjusted, repeat the adjustment method of the DIpulse combustion model to calibrate the cylinder pressure, heat release rate and exhaust temperature parameters.

[0092] Figure 3 and Figure 4 Before and after improvement Figure 1 Modeling process of DIPulse combustion model in .

[0093] In this embodiment, the DIPulse combustion model after the correction of fuel injection can achieve the power, torque, intercooler temperature, turbine exhaust temperature, explosion pressure and other parameters obtained from the diesel engine whole machine test and simulation to be consistent within the acceptable error range. The cylinder pressure and heat release rate curve verification results are as follows: Figure 5 shown.

[0094] The parts of the present invention that are not described in detail may refer to the prior art or are known to those skilled in the art.

[0095] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A method for matching parameters of a high-speed diesel engine quasi-dimensional combustion model, characterized in that: The method comprises: S1. Determine whether there is obvious afterburning phenomenon caused by abnormal fuel injection during the diesel engine test; if so, proceed to the next step; otherwise, end the matching; S2. Set the model injection parameters according to the test injection law, build the in-cylinder combustion model, and perform calibration based on the test cylinder pressure curve and heat release rate curve. After the in-cylinder process calibration is completed, perform the whole machine parameter calibration to determine whether there are abnormalities in the heat release rate and the exhaust temperature before and after the turbine. If yes, proceed to the next step, otherwise, terminate the matching; S3, changing the injection mode of the in-cylinder combustion model from pre-injection and main injection to main injection and post-injection, wherein the main injection parameters after the change are consistent with the main injection parameters before the change; determining the post-injection parameters according to the main injection parameters; Determine the post-spray parameters based on the main spray parameters, including: Reduce the main injection amount as the post injection amount; The end time of main injection is taken as the timing of post-injection; The post-injection pulse width is determined based on the diesel engine's afterburning degree and experience; The post-injection rate is determined based on the post-injection fuel quantity and post-injection pulse width; S4, using the in-cylinder combustion model obtained in S3 to perform simulation and obtain simulation data; S5. Compare the simulated cylinder pressure data with the experimental cylinder pressure data, the simulated heat release rate curve with the experimental heat release rate curve, and the simulated explosion pressure value with the experimental explosion pressure value; if the comparison result meets the requirements, the construction of the cylinder combustion model based on afterburning is completed, otherwise readjust the main injection and after-injection parameters and return to S4.

2. The high-speed diesel engine quasi-dimensional combustion model parameter matching method according to claim 1, characterized in that: The contents of judging whether there is obvious afterburning phenomenon during the diesel engine test include: Construct an in-cylinder combustion model and adjust the corresponding combustion parameters of the model according to the test data, including pre-injection and main injection parameters; Check cylinder pressure and heat release rate curves; Conduct model combustion simulation; Compare the simulated exhaust temperature parameters with the experimental exhaust temperature parameters; determine whether there is obvious afterburning based on the size relationship and difference between the two.

3. The high-speed diesel engine quasi-dimensional combustion model parameter matching method according to claim 2, characterized in that: When the simulated exhaust temperature parameter is lower than the tested exhaust temperature parameter and the difference between the two is greater than the first judgment threshold, it is determined that there is an obvious afterburning phenomenon, otherwise there is no obvious afterburning phenomenon.

4. The high-speed diesel engine quasi-dimensional combustion model parameter matching method according to claim 1, characterized in that: The main injection parameters in step S3 include: The main injection timing is determined based on the starting point of the test heat release rate; The main injection pulse width is determined according to the test ECU test; The main injection amount is determined according to the circulating oil amount; The main injection rate is determined by the circulating oil volume and pulse width.

5. The high-speed diesel engine quasi-dimensional combustion model parameter matching method according to any one of claims 1 to 4, characterized in that: When the main spray and post spray parameters are readjusted, the nozzle diameter and the number of nozzles remain unchanged.

6. The high-speed diesel engine quasi-dimensional combustion model parameter matching method according to claim 1, characterized in that: The content of determining the post-spray parameters according to the main spray parameters in step S3 includes: The main injection amount is reduced to simulate the initial combustion rate reduction caused by the injection fuel beam hitting the wall. In order to ensure that the circulating oil volume remains unchanged, the reduced main injection amount is used as the post-injection amount for the second injection. The end time of main injection is taken as the timing of post-injection; The post-spray pulse width is determined based on the degree of agreement between the heat release rate curve of the model simulation and the heat release rate curve of the test; The post-injection rate is determined by the post-injection fuel quantity and the post-injection pulse width.

7. The high-speed diesel engine quasi-dimensional combustion model parameter matching method according to claim 1, characterized in that: The method for matching parameters of the high-speed diesel engine quasi-dimensional combustion model also includes the following steps before step S1: S001. Build the GT-POWER diesel engine model, including the fuel injection system model; S002. Adjust the injection timing, injection pulse width and injector structural parameters of the model according to the test data.

8. The high-speed diesel engine quasi-dimensional combustion model parameter matching method according to claim 7, characterized in that: The method for matching parameters of the high-speed diesel engine quasi-dimensional combustion model also includes the following steps after step S5: S003. Adjust the entrainment coefficient, ignition delay coefficient, premixed combustion rate coefficient and diffusion combustion rate coefficient of the in-cylinder combustion model according to the test data; S004. Check the simulated cylinder pressure curve and the test cylinder pressure curve, and check the simulated heat release rate curve and the test heat release rate.

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