Engine exhaust temperature design method and system based on optimization of water jacket

Abstract

The application provides an engine exhaust temperature design method and system based on optimized water jacket, which comprises the following steps: area optimization is performed on a to-be-optimized region, and whether the flow velocity of the exhaust valve nose bridge area is greater than a first preset flow velocity threshold is judged; temperature field analysis is performed on the optimized cylinder head water jacket, and whether the temperature field analysis result meets a second preset condition is judged; heat balance test and checking are performed according to the 3D cylinder block and cylinder head finite element temperature field; after the checking is completed, the first heat transfer heat flow and the second heat transfer heat flow are compared and adjusted until the heat dissipation effect of the 1D cylinder block and cylinder head thermodynamic model and the 3D cylinder block and cylinder head finite element temperature field is within a first preset error threshold. The engine exhaust temperature is verified until the engine exhaust temperature obtained after iterative optimization is higher than a first exhaust temperature threshold under a preset working condition, and the final cylinder head water jacket temperature field is output. The engine exhaust temperature design method based on the optimized water jacket can ensure that the optimized water jacket reduces heat loss and improves the engine exhaust temperature.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine exhaust temperature design, and particularly relates to an engine exhaust temperature design method and system based on optimized water jacket. BACKGROUND

[0002] The function of the engine cooling system is to absorb and dissipate the excess heat of the heated parts of the engine, and to ensure the normal and stable operation of all components of the engine. Insufficient cooling or excessive cooling will affect the reliability and service life of the engine, leading to a decline in its working performance, and even unable to work normally in severe cases.

[0003] The distribution of the cooling liquid in the cooling water jacket directly affects the thermal load, cooling efficiency, and heat utilization and distribution of the engine parts. At present, in the design and research of the engine cooling water jacket, the distribution of the water jacket cooling area is not arranged according to the heat dissipation demand from the positive direction. It cannot be quantified, and in order to ensure the reliability of the cylinder block and head, the water jacket area is usually made as large as possible, which is easy to cause the phenomenon of over-cooling of the water jacket, and further leads to the exhaust temperature being too low. At the same time, due to the intermittent operation of the hybrid engine, the exhaust temperature rises slowly, which leads to the failure of the aftertreatment to work. SUMMARY

[0004] Therefore, the purpose of the present application is to provide an engine exhaust temperature design method and system based on optimized water jacket, so as to ensure the optimized water jacket to reduce heat loss while improving the engine exhaust temperature, thereby providing protection for the engine aftertreatment work.

[0005] According to the engine exhaust temperature design method based on the optimized water jacket provided by the present application, the method comprises:

[0006] determining a to-be-optimized area in the exhaust port water jacket based on the cylinder head water jacket temperature field, performing area optimization on the to-be-optimized area, and performing flow field analysis on the cylinder head water jacket after the area optimization, so as to obtain the exhaust valve nose beam area flow rate according to the flow field analysis result, and determine whether the exhaust valve nose beam area flow rate is greater than a first preset flow rate threshold value;

[0007] if the exhaust valve nose beam area flow rate is greater than the first preset flow rate threshold value, performing temperature field analysis on the optimized cylinder head water jacket to obtain a temperature field analysis result, and determining whether the temperature field analysis result meets a second preset condition;

[0008] if the temperature field analysis result meets the second preset condition, dividing the water jacket into structures, and constructing a 3D cylinder block and head finite element temperature field according to the structure division result, and performing thermal balance test and checking according to the 3D cylinder block and head finite element temperature field;

[0009] After the checking is completed, the first heat transfer heat flow of the exhaust passage wall surface in the 3D cylinder head finite element temperature field is extracted, and a 1D cylinder head thermodynamic model is established, so as to compare the first heat transfer heat flow and the second heat transfer heat flow calculated based on the 1D cylinder head thermodynamic model, and adjust until the heat dissipation effect of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field is within the first preset error threshold;

[0010] The engine exhaust temperature is verified whether it is higher than the first exhaust temperature threshold under the preset working condition, if the engine exhaust temperature is lower than or equal to the first exhaust temperature threshold under the preset working condition, the optimized cylinder head water jacket temperature field is re-evaluated whether there is a to-be-optimized area, until the engine exhaust temperature obtained after iterative optimization is higher than the first exhaust temperature threshold under the preset working condition, and the final cylinder head water jacket temperature field is output.

[0011] In summary, according to the above-mentioned engine exhaust temperature design method based on optimized water jacket, coupling analysis is carried out through 3D temperature field and 1D thermodynamic method, which ensures that the optimized water jacket reduces heat loss while improving engine exhaust temperature, thereby providing guarantee for engine aftertreatment work. Specifically, first, the to-be-optimized area is determined based on the cylinder head water jacket temperature field, then the to-be-optimized area is optimized, and then the optimized cylinder head water jacket is analyzed in flow field, temperature field and thermal balance test. When the flow field analysis, temperature field analysis and thermal balance test all meet the requirements, the 1D cylinder head thermodynamic model is established, and the heat dissipation effect of the 1D cylinder head thermodynamic model is analyzed whether it is within the error based on the 3D cylinder head finite element temperature field. If it is confirmed that the heat dissipation effect is consistent, it is verified whether the engine exhaust temperature meets the actual requirements. Through accurate and quantitative analysis of each step of engine exhaust temperature design, the traditional way of improving engine exhaust temperature by frequently optimizing water jacket is replaced, and the way of water jacket overcooling is avoided. The engine exhaust temperature is effectively improved while the water jacket is optimized, thereby providing guarantee for engine aftertreatment work.

[0012] Further, the step of determining the to-be-optimized area in the exhaust passage water jacket based on the cylinder head water jacket temperature field, area-optimizing the to-be-optimized area, and analyzing the flow field of the area-optimized cylinder head water jacket to obtain the exhaust valve nose beam area flow rate and determine whether the exhaust valve nose beam area flow rate is greater than the first preset flow rate threshold comprises:

[0013] Numerical simulation of the cylinder head water jacket temperature field of the target engine is performed to obtain a safety coefficient distribution result, and a to-be-optimized area in the exhaust passage water jacket wall surface that meets a first preset condition is screened out according to the safety coefficient distribution result, the first preset condition being an area in the water jacket wall surface with a temperature lower than a first preset temperature threshold and a safety coefficient higher than a first preset safety coefficient threshold;

[0014] An area of the to-be-optimized region is obtained, and the area of the to-be-optimized region is reduced by a first preset proportion to obtain an optimized to-be-optimized region.

[0015] Further, the temperature field analysis result includes a cylinder head temperature and an exhaust water jacket wall surface temperature, and if the exhaust valve nose bridge area flow rate is greater than a first preset flow rate threshold, the step of performing temperature field analysis on the optimized cylinder head water jacket to obtain a temperature field analysis result and determining whether the temperature field analysis result satisfies a second preset condition includes:

[0016] determining whether the cylinder head temperature is less than or equal to a second preset temperature threshold and whether the exhaust water jacket wall surface temperature is less than or equal to a third preset temperature threshold;

[0017] if the cylinder head temperature is less than or equal to the second preset temperature threshold and the exhaust water jacket wall surface temperature is less than or equal to the third preset temperature threshold, it is determined that the temperature field analysis result satisfies the second preset condition;

[0018] if the cylinder head temperature is greater than the second preset temperature threshold and / or the exhaust water jacket wall surface temperature is greater than the third preset temperature threshold, the area of the optimized to-be-optimized region is increased by a second preset proportion, and the second preset proportion is less than the first preset proportion;

[0019] temperature field analysis is performed again until the temperature field analysis result satisfies the second preset condition.

[0020] Further, if the temperature field analysis result satisfies the second preset condition, the water jacket is divided into structures, and a 3D cylinder block and cylinder head finite element temperature field is constructed according to the structure division result, and a thermal balance test and checking are performed according to the 3D cylinder block and cylinder head finite element temperature field.

[0021] The water jacket is divided into a cylinder block cooling water jacket, a cylinder head lower water jacket, a cylinder head upper water jacket, and an exhaust manifold cooling water jacket.

[0022] Based on the 3D cylinder block and cylinder head finite element temperature field, an input heat composition entering the cylinder block and cylinder head is counted, and the input heat composition includes heat of a cylinder head fire surface, a cylinder head exhaust passage, a cylinder block hole, and intake and exhaust valves, so as to calculate a total input heat according to the heat of the cylinder head fire surface, the cylinder head exhaust passage, the cylinder block hole, and the intake and exhaust valves.

[0023] Based on the 3D cylinder block and cylinder head finite element temperature field, an output heat composition flowing out of the cylinder block and cylinder head is counted, and the output heat composition includes heat of the cylinder block cooling water jacket, the cylinder head lower water jacket, the cylinder head upper water jacket, and the exhaust manifold cooling water jacket, so as to calculate a total output heat according to the heat of the cylinder block cooling water jacket, the cylinder head lower water jacket, the cylinder head upper water jacket, and the exhaust manifold cooling water jacket.

[0024] Furthermore, the steps of dividing the water jacket into structural sections if the temperature field analysis results meet the second preset condition, constructing a 3D cylinder block and cylinder head finite element temperature field based on the structural sectioning results, and performing thermal balance testing and verification based on the 3D cylinder block and cylinder head finite element temperature field also include:

[0025] A first error value is calculated based on the total input heat and the total output heat, and it is determined whether the first error value is less than a second preset error threshold.

[0026] If the first error value is less than the second preset error threshold, it is determined that the finite element temperature field of the 3D cylinder block and cylinder head has reached the thermal equilibrium standard.

[0027] If the first error value is greater than or equal to the second preset error threshold, the finite element temperature field of the 3D cylinder block and cylinder head is checked until the finite element temperature field of the 3D cylinder block and cylinder head reaches the thermal balance standard.

[0028] Further, after the verification is completed, the first heat transfer flux of the exhaust manifold wall surface in the 3D cylinder block and cylinder head finite element temperature field is extracted, and a 1D cylinder block and cylinder head thermodynamic model is established. The second heat transfer flux of the exhaust manifold wall surface calculated based on the 1D cylinder block and cylinder head thermodynamic model is used. The first heat transfer flux and the second heat transfer flux are compared and adjusted until the heat dissipation effect of the 1D cylinder block and cylinder head thermodynamic model and the 3D cylinder block and cylinder head finite element temperature field is within a first preset error threshold. The steps include:

[0029] From the 3D cylinder block and cylinder head temperature field calculation, the temperatures of the cylinder bore, piston, cylinder head combustion chamber, and exhaust manifold walls are extracted to define the wall temperatures of the combustion gas heat exchange in the 1D cylinder block and cylinder head thermodynamic model based on the temperatures of the cylinder bore, piston, cylinder head combustion chamber, and exhaust manifold walls.

[0030] The exhaust gas side of the 1D cylinder block and cylinder head thermodynamic model is discretized into multiple regular pipes. The temperature of each pipe is obtained from the 3D cylinder block and cylinder head temperature field, and the pipes in the 1D cylinder block and cylinder head thermodynamic model are assigned values ​​respectively. Then, the second heat transfer flow rate is calculated based on the 1D cylinder block and cylinder head thermodynamic model.

[0031] Furthermore, after the step of discretizing the exhaust gas side of the 1D cylinder block and cylinder head thermodynamic model into multiple regular pipes, assigning values ​​to the pipes in the 1D cylinder block and cylinder head thermodynamic model according to the temperature of each pipe obtained from the 3D cylinder block and cylinder head temperature field, and then calculating the second heat transfer flow rate based on the 1D cylinder block and cylinder head thermodynamic model, the method further includes:

[0032] Calculate the first or second heat transfer flow rate using the following formula:

[0033] Φ=Ak(t f1 -t f2 )

[0034] Φ represents the heat transfer heat flow, the unit is W, k represents the heat transfer coefficient, the unit is W / (m 2 .K), A represents the heat exchange area of the exhaust passage wall surface, the unit is m 2 f1 t f2 represents the exhaust passage wall surface temperature;

[0035] The second error value is calculated according to the first heat transfer heat flow and the second heat transfer heat flow, and it is judged whether the second error value is less than the first preset error threshold;

[0036] If the second error value is less than the first preset error threshold, it is determined that the heat dissipation effect of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field is consistent;

[0037] If the second error value is greater than or equal to the first preset error threshold, the wall surface temperature of the gas heat exchange in the 1D cylinder head thermodynamic model is increased or decreased according to the third preset ratio, and the heat dissipation effect of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field is re-evaluated until the heat dissipation effect of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field is consistent.

[0038] Another aspect of the present application also provides an engine exhaust temperature design system based on optimized water jacket, the system comprises:

[0039] The exhaust passage water jacket optimization module is used for determining the to-be-optimized area in the exhaust passage water jacket based on the cylinder head temperature field, performing area optimization on the to-be-optimized area, and performing flow field analysis on the cylinder head water jacket after area optimization, so as to obtain the exhaust valve nose beam area flow rate according to the flow field analysis result, and judge whether the exhaust valve nose beam area flow rate is greater than the first preset flow rate threshold;

[0040] The temperature field analysis module is used for performing temperature field analysis on the optimized cylinder head water jacket if the exhaust valve nose beam area flow rate is greater than the first preset flow rate threshold, obtaining a temperature field analysis result, and judging whether the temperature field analysis result satisfies the second preset condition;

[0041] The heat balance checking module is used for dividing the water jacket into structures if the temperature field analysis result satisfies the second preset condition, constructing a 3D cylinder head finite element temperature field according to the structure division result, and performing heat balance test and checking according to the 3D cylinder head finite element temperature field;

[0042] ​a thermodynamic analysis module, configured to, after the completion, extract a first heat transfer heat flow of an exhaust passage wall surface in a 3D cylinder head finite element temperature field, and establish a 1D cylinder head thermodynamic model, so as to compare and adjust a second heat transfer heat flow of the exhaust passage wall surface calculated based on the 1D cylinder head thermodynamic model and the first heat transfer heat flow until the heat dissipation effect of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field is within a first preset error threshold;

[0043] a verification module, configured to verify whether the engine exhaust temperature is higher than a first exhaust temperature threshold under a preset working condition, and if the engine exhaust temperature is lower than or equal to the first exhaust temperature threshold under the preset working condition, re-evaluate whether the optimized cylinder head water jacket temperature field has a to-be-optimized area, until the engine exhaust temperature obtained after the iterative optimization is higher than the first exhaust temperature threshold under the preset working condition, and output a final cylinder head water jacket temperature field.

[0044] Further, the exhaust passage water jacket optimization module further comprises:

[0045] a to-be-optimized area screening unit, configured to perform a cylinder head water jacket temperature field numerical simulation on a target engine to obtain a safety coefficient distribution result, and screen a to-be-optimized area in the exhaust passage water jacket wall surface that meets a first preset condition according to the safety coefficient distribution result, the first preset condition being an area in the water jacket wall surface with a temperature lower than a first preset temperature threshold and a safety coefficient higher than a first preset safety coefficient threshold;

[0046] an optimization execution unit, configured to obtain an area of the to-be-optimized area, and reduce the area of the to-be-optimized area by a first preset proportion to obtain an optimized to-be-optimized area.

[0047] Further, the temperature field analysis module further comprises:

[0048] a cylinder head temperature detection unit, configured to judge whether the cylinder head temperature is less than or equal to a second preset temperature threshold and whether the exhaust water jacket wall surface temperature is less than or equal to a third preset temperature threshold;

[0049] a first determination unit, configured to determine that the temperature field analysis result meets a second preset condition if the cylinder head temperature is less than or equal to the second preset temperature threshold and the exhaust water jacket wall surface temperature is less than or equal to the third preset temperature threshold;

[0050] a second determination unit, configured to increase the area of the optimized to-be-optimized area by a second preset proportion if the cylinder head temperature is greater than the second preset temperature threshold and / or the exhaust water jacket wall surface temperature is greater than the third preset temperature threshold, the second preset proportion being less than the first preset proportion;

[0051] re-perform the temperature field analysis until the temperature field analysis result meets the second preset condition.

[0052] Additional aspects and advantages of the present application will be made apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 A flow chart of an engine exhaust temperature design method based on an optimized water jacket according to a first embodiment of the present application;

[0054] Figure 2 A division diagram of a water jacket structure according to the first embodiment of the present application;

[0055] Figure 3 A discrete diagram of a gas side of an exhaust passage according to the first embodiment of the present application;

[0056] Figure 4 A structure diagram of an engine exhaust temperature design system based on an optimized water jacket according to a second embodiment of the present application.

[0057] The following detailed description will further describe the present application with reference to the above-mentioned drawings. DETAILED DESCRIPTION

[0058] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The drawings show several embodiments of the present application. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided so that the disclosure of the present application is more thorough and complete.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terminology used in the description of the present application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0060] Referring to Figure 1 , a flow chart of an engine exhaust temperature design method based on an optimized water jacket according to a first embodiment of the present application is shown, which includes steps S01 to S05, wherein:

[0061] Step S01: determining a to-be-optimized region in an exhaust passage water jacket based on a cylinder head water jacket temperature field, performing area optimization on the to-be-optimized region, and performing flow field analysis on the cylinder head water jacket after area optimization to obtain an exhaust valve nose bridge region flow rate according to the flow field analysis result and determine whether the exhaust valve nose bridge region flow rate is greater than a first preset flow rate threshold;

[0062] It should be noted that in some optional embodiments of the present application, when the exhaust passage water jacket area to be optimized is determined, the numerical simulation of the cylinder head water jacket temperature field of the target engine is first performed to obtain the safety factor distribution result, and the area to be optimized in the exhaust passage water jacket wall surface that meets the first preset condition is screened out according to the safety factor distribution result, the first preset condition being the area in the water jacket wall surface where the temperature is lower than the first preset temperature threshold and the safety factor is higher than the first preset safety factor threshold.

[0063] Then the area of the area to be optimized is obtained, and the area of the area to be optimized is reduced by the first preset proportion to obtain the optimized area to be optimized.

[0064] It can be understood that in order to quantitatively and accurately evaluate the optimized water jacket, the area to be optimized is first screened out based on a specific first preset condition, and then the area to be optimized is optimized according to the first preset proportion. For example, but not limited to, in this embodiment, the first preset temperature threshold is 160℃, the first preset safety factor threshold is 1.6, and the first preset proportion is 20%, i.e. the area of the exhaust passage water jacket is reduced by 20% each time. In other embodiments of the present application, the first preset temperature threshold, the first preset safety factor threshold and the first preset proportion can also be set to other values according to other actual conditions.

[0065] Step S02: If the exhaust valve nose bridge area flow rate is greater than the first preset flow rate threshold, the optimized cylinder head water jacket is subjected to temperature field analysis to obtain a temperature field analysis result, and it is determined whether the temperature field analysis result meets a second preset condition;

[0066] It should be noted that the temperature field analysis result includes the cylinder head temperature and the exhaust water jacket wall surface temperature. In some optional embodiments of the present application, the temperature field analysis process is as follows:

[0067] First, it is determined whether the cylinder head temperature is less than or equal to a second preset temperature threshold and whether the exhaust water jacket wall surface temperature is less than or equal to a third preset temperature threshold;

[0068] If the cylinder head temperature is less than or equal to the second preset temperature threshold and the exhaust water jacket wall surface temperature is less than or equal to the third preset temperature threshold, it is determined that the temperature field analysis result meets the second preset condition;

[0069] If the cylinder head temperature is greater than the second preset temperature threshold and / or the exhaust water jacket wall surface temperature is greater than the third preset temperature threshold, the area of the optimized area to be optimized is increased by a second preset proportion, the second preset proportion being less than the first preset proportion, and the temperature field analysis is performed again until the temperature field analysis result meets the second preset condition.

[0070] By way of example but not limitation, in this embodiment, the first preset flow rate threshold is 3 m / s, the second preset proportion is ten percent, the second preset temperature threshold is 260°C, and the third preset temperature threshold is 160°C. It can be understood that in other embodiments of the present application, the first preset flow rate threshold, the second preset proportion, the second preset temperature threshold, and the third preset temperature threshold can also be set to other values according to actual needs.

[0071] Step S03: If the temperature field analysis result meets the second preset condition, the water jacket is structurally divided, and a 3D cylinder head finite element temperature field is constructed according to the structural division result, and a thermal balance test and checking are performed according to the 3D cylinder head finite element temperature field.

[0072] In this step, please refer to FIG. 3, which is a schematic diagram of water jacket structural division, and specifically, the water jacket is divided into a cylinder body cooling water jacket, a cylinder head lower water jacket, a cylinder head upper water jacket, and an exhaust manifold cooling water jacket. Figure 2

[0073] Based on the 3D cylinder head finite element temperature field, a composition of input heat entering the cylinder head is counted, and the composition of input heat includes heat of a cylinder head fire surface, a cylinder head exhaust passage, a cylinder body hole, and intake and exhaust valves, so that the total input heat is calculated according to the heat of the cylinder head fire surface, the cylinder head exhaust passage, the cylinder body hole, and the intake and exhaust valves.

[0074] Based on the 3D cylinder head finite element temperature field, a composition of output heat flowing out of the cylinder head is counted, and the composition of output heat includes heat of the cylinder body cooling water jacket, the cylinder head lower water jacket, the cylinder head upper water jacket, and the exhaust manifold cooling water jacket, so that the total output heat is calculated according to the heat of the cylinder body cooling water jacket, the cylinder head lower water jacket, the cylinder head upper water jacket, and the exhaust manifold cooling water jacket.

[0075] A first error value is calculated according to the total input heat and the total output heat, and it is determined whether the first error value is less than a second preset error threshold; the first error value is equal to a difference between the total input heat and the total output heat divided by the total input heat.

[0076] If the first error value is less than the second preset error threshold, it is determined that the 3D cylinder head finite element temperature field reaches a thermal balance standard.

[0077] If the first error value is greater than or equal to the second preset error threshold, the 3D cylinder head finite element temperature field is checked until the 3D cylinder head finite element temperature field reaches the thermal balance standard.

[0078] By way of example but not limitation, the checking process specifically adjusts calculation parameters of a thermal boundary in the 3D cylinder head finite element temperature field, such as setting of a heat exchange boundary layer, and the second preset error value is set to five percent.

[0079] ​Step S04: After the check is completed, the first heat transfer heat flow of the exhaust port wall surface in the 3D cylinder head finite element temperature field is extracted, and a 1D cylinder head thermodynamic model is established. The second heat transfer heat flow of the exhaust port wall surface calculated based on the 1D cylinder head thermodynamic model is obtained, and the first heat transfer heat flow and the second heat transfer heat flow are compared and adjusted until the heat dissipation effect of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field is within the first preset error threshold;

[0080] In order to avoid the problem of water jacket overcooling leading to low exhaust temperature, in this step, coupling analysis is carried out by 3D temperature field and 1D thermodynamic method, which ensures that the water jacket is optimized to reduce heat loss while improving the engine exhaust temperature. The specific steps are as follows:

[0081] From the 3D cylinder head temperature field calculation, the temperature of the cylinder hole, piston, cylinder head combustion chamber and exhaust port wall surface is extracted to define the wall surface temperature of the gas heat exchange in the 1D cylinder head thermodynamic model according to the temperature of the cylinder hole, piston, cylinder head combustion chamber and exhaust port wall surface;

[0082] The exhaust port gas side in the 1D cylinder head thermodynamic model is discretized into multiple regular pipelines, please refer to Figure 3 , which is an exhaust port gas side discretization diagram, and each pipeline in the 1D cylinder head thermodynamic model is valued according to the temperature of each pipeline obtained from the 3D cylinder head temperature field, and the second heat transfer heat flow is calculated based on the 1D cylinder head thermodynamic model;

[0083] The first heat transfer heat flow or the second heat transfer heat flow is calculated according to the following formula:

[0084] Φ = Ak (t f1 -t f2 )

[0085] Φ represents the heat transfer heat flow, the unit is W, k represents the heat transfer coefficient, the unit is W / (m 2 .K), A represents the heat transfer area of the exhaust port wall surface, the unit is m 2 , t f1 represents the gas temperature, t f2 represents the exhaust port wall surface temperature;

[0086] The second error value is calculated according to the first heat transfer heat flow and the second heat transfer heat flow, and it is judged whether the second error value is less than the first preset error threshold;

[0087] If the second error value is less than the first preset error threshold, it is determined that the heat dissipation effect of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field is consistent;

[0088] If the second error value is greater than or equal to the first preset error threshold, the wall temperature of the gas heat exchange in the 1D cylinder head thermodynamic model is increased or decreased by a third preset ratio, and the heat dissipation effect of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field is re-evaluated until the heat dissipation effect of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field is consistent. For example, the first preset error threshold is 5%.

[0089] It should be pointed out that, since the exhaust passage gas side wall heat flow is the most critical part, in this embodiment, the 3D temperature field calculation heat flow is taken as the benchmark, and all wall temperatures are increased or decreased by a ratio until the 1D thermodynamic calculation heat flow and the 3D cylinder head temperature field heat flow calculation error is less than the first preset error threshold.

[0090] Specifically, if the first heat transfer heat flow is greater than the second heat transfer heat flow, the wall temperature of the 1D cylinder head thermodynamic model needs to be increased by a ratio, and then the heat dissipation effect of the 1D thermodynamic calculation heat flow and the 3D cylinder head temperature field is re-evaluated.

[0091] If the first heat transfer heat flow is less than the second heat transfer heat flow, the wall temperature of the 1D cylinder head thermodynamic model needs to be decreased by a ratio, and then the heat dissipation effect of the 1D thermodynamic calculation heat flow and the 3D cylinder head temperature field is re-evaluated.

[0092] Step S05: verifying whether the engine exhaust temperature is higher than the first exhaust temperature threshold under the preset working condition, if the engine exhaust temperature is lower than or equal to the first exhaust temperature threshold under the preset working condition, re-evaluating whether the optimized cylinder head water jacket temperature field has an area to be optimized, until the engine exhaust temperature after iterative optimization is higher than the first exhaust temperature threshold under the preset working condition, and outputting the final cylinder head water jacket temperature field.

[0093] It should be noted that after the heat dissipation effect of the 1D thermodynamic calculation heat flow and the 3D cylinder head temperature field is consistent, the exhaust temperature is re-evaluated to determine whether it meets the requirements. If it is still low, the water jacket area needs to be further reduced, and the above steps are repeated to re-calculate the heat dissipation effect and the exhaust temperature until the exhaust temperature meets the requirements. For example, under the working condition of 2000 rpm, BMEP, 12 bar, the exhaust temperature increases from 550℃ to 580℃, and the exhaust temperature under this working condition is at least 570℃, that is, the exhaust temperature is determined to meet the requirements.

[0094] Further, if the engine exhaust temperature is lower than or equal to the first exhaust temperature threshold under the preset working condition, it means that the engine exhaust temperature does not meet the requirements, at this time the area to be optimized needs to be re-confirmed, and iterative optimization is performed until the engine exhaust temperature is higher than the first exhaust temperature threshold under the preset working condition.

[0095] Further, after the exhaust temperature meets the requirement, the structural strength after the water jacket is changed is checked again to ensure that the safety factor of the result strength after the thermal stress increases due to the increase of the cylinder head temperature meets the requirement, and if the result strength fatigue safety factor has a problem, the local chamfer of the problematic area is continuously increased to optimize and improve the safety factor until the structural strength requirement is finally met.

[0096] In summary, according to the engine exhaust temperature design method based on the optimized water jacket, the coupling analysis is performed through the 3D temperature field and the 1D thermodynamic method, the optimized water jacket is ensured to reduce the heat loss, and the engine exhaust temperature is improved, thereby providing protection for the engine aftertreatment work. Specifically, first, the to-be-optimized area is determined based on the cylinder head water jacket temperature field, then the to-be-optimized area is optimized, and then the optimized cylinder head water jacket is analyzed in terms of flow field, temperature field and thermal balance test. When the flow field analysis, temperature field analysis and thermal balance test all meet the requirements, the 1D cylinder block and cylinder head thermodynamic model is established, and whether the heat dissipation effect of the 1D cylinder block and cylinder head thermodynamic model is within the error range is analyzed based on the 3D cylinder block and cylinder head finite element temperature field. If it is confirmed that the heat dissipation effect is consistent, it is verified whether the engine exhaust temperature meets the actual requirement. Through the accurate and quantitative analysis of each step of the design of the engine exhaust temperature, the traditional way of improving the engine exhaust temperature by frequently optimizing the water jacket is replaced, the way of overcooling the water jacket is avoided, the engine exhaust temperature is effectively improved while the water jacket is optimized, and protection is provided for the engine aftertreatment work.

[0097] Please refer to Figure 4 , which is a structure schematic diagram of an engine exhaust temperature design system based on an optimized water jacket in the second embodiment of the present application. The system comprises:

[0098] The exhaust port water jacket optimization module 10 is configured to determine a to-be-optimized area in the exhaust port water jacket based on the cylinder head water jacket temperature field, perform area optimization on the to-be-optimized area, and perform flow field analysis on the cylinder head water jacket after the area optimization, so as to obtain the exhaust valve nose beam area flow rate according to the flow field analysis result and determine whether the exhaust valve nose beam area flow rate is greater than a first preset flow rate threshold.

[0099] Further, the exhaust port water jacket optimization module 10 further comprises:

[0100] The to-be-optimized area screening unit is configured to perform numerical simulation on the cylinder head water jacket temperature field of the target engine to obtain a safety factor distribution result, and screen out a to-be-optimized area in the exhaust port water jacket wall surface that meets a first preset condition according to the safety factor distribution result. The first preset condition is a region in the water jacket wall surface where the temperature is lower than a first preset temperature threshold and the safety factor is higher than a first preset safety factor threshold.

[0101] An optimization execution unit is configured to acquire an area of the to-be-optimized region and reduce the area of the to-be-optimized region by a first preset proportion to obtain an optimized to-be-optimized region.

[0102] A temperature field analysis module 20 is configured to perform temperature field analysis on the optimized cylinder head water jacket if the exhaust valve nose bridge region flow rate is greater than a first preset flow rate threshold value, to obtain a temperature field analysis result, and to determine whether the temperature field analysis result satisfies a second preset condition.

[0103] Further, the temperature field analysis module 20 further comprises:

[0104] A cylinder head temperature detection unit is configured to determine whether the cylinder head temperature is less than or equal to a second preset temperature threshold value and whether the exhaust water jacket wall surface temperature is less than or equal to a third preset temperature threshold value.

[0105] A first determination unit is configured to determine that the temperature field analysis result satisfies the second preset condition if the cylinder head temperature is less than or equal to the second preset temperature threshold value and the exhaust water jacket wall surface temperature is less than or equal to the third preset temperature threshold value.

[0106] A second determination unit is configured to increase the area of the optimized to-be-optimized region by a second preset proportion if the cylinder head temperature is greater than the second preset temperature threshold value and / or the exhaust water jacket wall surface temperature is greater than the third preset temperature threshold value, the second preset proportion being less than the first preset proportion.

[0107] The temperature field analysis is performed again until the temperature field analysis result satisfies the second preset condition.

[0108] A thermal balance checking module 30 is configured to divide the water jacket into structures if the temperature field analysis result satisfies the second preset condition, to construct a 3D cylinder block and cylinder head finite element temperature field according to the structure division result, and to perform thermal balance testing and checking according to the 3D cylinder block and cylinder head finite element temperature field.

[0109] Further, the thermal balance checking module further comprises:

[0110] A water jacket structure division unit is configured to divide the water jacket into a cylinder block cooling water jacket, a cylinder head lower water jacket, a cylinder head upper water jacket, and an exhaust manifold cooling water jacket.

[0111] A total input heat calculation unit is configured to statistically acquire an input heat composition into the cylinder block and cylinder head based on the 3D cylinder block and cylinder head finite element temperature field, the input heat composition including heat of a cylinder head fire surface, a cylinder head exhaust passage, a cylinder block hole, and intake and exhaust valves, to calculate the total input heat according to the heat of the cylinder head fire surface, the cylinder head exhaust passage, the cylinder block hole, and the intake and exhaust valves.

[0112] a total output heat calculation unit configured to calculate a total output heat based on a composition of output heat flowing out of the 3D cylinder head from the 3D cylinder head finite element temperature field, the composition of output heat including heat of the cylinder cooling water jacket, the lower cylinder head water jacket, the upper cylinder head water jacket, and the exhaust manifold cooling water jacket, so as to calculate the total output heat according to the heat of the cylinder cooling water jacket, the lower cylinder head water jacket, the upper cylinder head water jacket, and the exhaust manifold cooling water jacket;

[0113] a heat dissipation effect detection unit configured to calculate a first error value according to the total input heat and the total output heat, and to determine whether the first error value is less than a second preset error threshold value;

[0114] a heat balance determination unit configured to determine that the 3D cylinder head finite element temperature field reaches a heat balance standard if the first error value is less than the second preset error threshold value;

[0115] a checking execution unit configured to check the 3D cylinder head finite element temperature field if the first error value is greater than or equal to the second preset error threshold value, until the 3D cylinder head finite element temperature field reaches the heat balance standard.

[0116] a thermodynamic analysis module 40 configured to, after the checking is completed, extract a first heat transfer heat flow of an exhaust port wall surface in the 3D cylinder head finite element temperature field, and establish a 1D cylinder head thermodynamic model, so as to compare and adjust the first heat transfer heat flow and a second heat transfer heat flow calculated based on the 1D cylinder head thermodynamic model until the heat dissipation effect of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field is within a first preset error threshold value;

[0117] Further, the thermodynamic analysis module 40 further comprises:

[0118] a wall surface temperature definition unit configured to extract temperatures of a cylinder bore, a piston, a cylinder head combustion chamber, and an exhaust port wall surface from the 3D cylinder head temperature field calculation, so as to define wall surface temperatures of gas heat exchange in the 1D cylinder head thermodynamic model according to the temperatures of the cylinder bore, the piston, the cylinder head combustion chamber, and the exhaust port wall surface;

[0119] a heat transfer heat flow calculation unit configured to discretize an exhaust port gas side in the 1D cylinder head thermodynamic model into a plurality of regular pipelines, and respectively assign the pipelines in the 1D cylinder head thermodynamic model according to temperatures of each pipeline obtained from the 3D cylinder head temperature field, and then calculate the second heat transfer heat flow based on the 1D cylinder head thermodynamic model;

[0120] The first heat transfer heat flow or the second heat transfer heat flow is calculated according to the following formula:

[0121] Φ = Ak (t f1 -t f2 )

[0122] Φ represents the heat transfer heat flow, the unit is W, k represents the heat transfer coefficient, the unit is W / (m 2 .K), A represents the heat exchange area of the exhaust passage wall surface, the unit is m 2 , t f1 represents the gas temperature, t f2 represents the exhaust passage wall surface temperature;

[0123] The heat dissipation effect detection unit is configured to calculate a second error value according to the first heat transfer heat flow and the second heat transfer heat flow, and determine whether the second error value is less than a first preset error threshold;

[0124] The heat dissipation effect determination unit is configured to determine that the heat dissipation effect of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field is consistent if the second error value is less than the first preset error threshold.

[0125] The wall surface temperature adjustment unit is configured to increase or decrease the wall surface temperature of the gas heat exchange in the 1D cylinder head thermodynamic model by a third preset ratio if the second error value is greater than or equal to the first preset error threshold, and re-evaluate the heat dissipation effect of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field until the heat dissipation effect of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field is consistent.

[0126] The verification module 50 is configured to verify whether the engine exhaust temperature is higher than a first exhaust temperature threshold under a preset working condition, and re-evaluate whether there is an optimization area in the optimized cylinder head water jacket temperature field if the engine exhaust temperature is lower than or equal to the first exhaust temperature threshold under the preset working condition, until the engine exhaust temperature obtained after iterative optimization is higher than the first exhaust temperature threshold under the preset working condition, and output the final cylinder head water jacket temperature field.

[0127] In summary, according to the engine exhaust temperature design system based on the optimized water jacket described above, the coupling analysis is performed through the 3D temperature field and the 1D thermodynamic method, so as to ensure that the optimized water jacket reduces the heat loss while improving the engine exhaust temperature, thereby providing guarantee for the engine aftertreatment work. Specifically, first, the to-be-optimized region is determined based on the cylinder head water jacket temperature field, and then the to-be-optimized region is optimized, and then the optimized cylinder head water jacket is analyzed in terms of flow field, temperature field and heat balance test. When the flow field analysis, temperature field analysis and heat balance test all meet the requirements, the 1D cylinder block and cylinder head thermodynamic model is established, and the heat dissipation effect of the 1D cylinder block and cylinder head thermodynamic model is analyzed based on the 3D cylinder block and cylinder head finite element temperature field. If it is confirmed that the heat dissipation effect is consistent, it is verified whether the engine exhaust temperature meets the actual requirements. Through the accurate and quantitative analysis of each step of the design of the engine exhaust temperature, the traditional method of improving the engine exhaust temperature by frequently optimizing the water jacket is replaced, the overcooling of the water jacket is avoided, the engine exhaust temperature is effectively improved while the water jacket is optimized, and guarantee is provided for the engine aftertreatment work.

[0128] In the description of the present specification, the description referring to the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0129] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that, for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for designing an engine exhaust temperature based on optimizing a water jacket, characterized by, The method comprises: determining a to-be-optimized region in the exhaust passage water jacket based on the cylinder head water jacket temperature field, performing area optimization on the to-be-optimized region, performing flow field analysis on the cylinder head water jacket after the area optimization, obtaining an exhaust valve nose beam region flow rate according to the flow field analysis result, and determining whether the exhaust valve nose beam region flow rate is greater than a first preset flow rate threshold value; if the exhaust valve nose beam region flow rate is greater than the first preset flow rate threshold value, performing temperature field analysis on the optimized cylinder head water jacket, obtaining a temperature field analysis result, and determining whether the temperature field analysis result satisfies a second preset condition; if the temperature field analysis result satisfies the second preset condition, performing structure division on the water jacket, constructing a 3D cylinder block and cylinder head finite element temperature field according to the structure division result, and performing heat balance testing and checking according to the 3D cylinder block and cylinder head finite element temperature field; after the checking is completed, extracting a first heat transfer heat flow of an exhaust passage wall surface in the 3D cylinder block and cylinder head finite element temperature field, establishing a 1D cylinder block and cylinder head thermodynamic model, comparing and adjusting a second heat transfer heat flow of the exhaust passage wall surface calculated based on the 1D cylinder block and cylinder head thermodynamic model and the first heat transfer heat flow until the heat dissipation effects of the 1D cylinder block and cylinder head thermodynamic model and the 3D cylinder block and cylinder head finite element temperature field are within a first preset error threshold value; verifying whether the engine exhaust temperature is higher than a first exhaust temperature threshold value under a preset working condition, and if the engine exhaust temperature is lower than or equal to the first exhaust temperature threshold value under the preset working condition, re-evaluating whether there is a to-be-optimized region in the optimized cylinder head water jacket temperature field until the engine exhaust temperature obtained after the iterative optimization is higher than the first exhaust temperature threshold value under the preset working condition, and outputting a final cylinder head water jacket temperature field.

2. The method of designing an engine exhaust gas temperature based on an optimized water jacket according to claim 1, wherein, The step of determining a to-be-optimized region in the exhaust passage water jacket based on the cylinder head water jacket temperature field, performing area optimization on the to-be-optimized region, and performing flow field analysis on the cylinder head water jacket after the area optimization to obtain an exhaust valve nose beam region flow rate according to the flow field analysis result and determine whether the exhaust valve nose beam region flow rate is greater than a first preset flow rate threshold value comprises: performing numerical simulation on the cylinder head water jacket temperature field of the target engine to obtain a safety coefficient distribution result, and screening out a to-be-optimized region in the exhaust passage water jacket wall surface that satisfies a first preset condition according to the safety coefficient distribution result, the first preset condition being a region in the water jacket wall surface with a temperature lower than a first preset temperature threshold value and a safety coefficient higher than a first preset safety coefficient threshold value; obtaining the area of the to-be-optimized region and reducing the area of the to-be-optimized region by a first preset proportion to obtain an optimized to-be-optimized region.

3. The method of designing an engine exhaust gas temperature based on an optimized water jacket according to claim 2, wherein, The temperature field analysis result comprises a cylinder head temperature and an exhaust water jacket wall surface temperature, and the step of, if the exhaust valve nose beam region flow rate is greater than the first preset flow rate threshold value, performing temperature field analysis on the optimized cylinder head water jacket to obtain a temperature field analysis result and determining whether the temperature field analysis result satisfies a second preset condition comprises: determining whether the cylinder head temperature is less than or equal to a second preset temperature threshold value and whether the exhaust water jacket wall surface temperature is less than or equal to a third preset temperature threshold value; If the cylinder head temperature is less than or equal to a second preset temperature threshold and the exhaust jacket wall temperature is less than or equal to a third preset temperature threshold, it is determined that the temperature field analysis result meets a second preset condition; If the cylinder head temperature is greater than the second preset temperature threshold and / or the exhaust jacket wall temperature is greater than the third preset temperature threshold, the area of the optimized region to be optimized is increased by a second preset proportion, and the second preset proportion is less than the first preset proportion; The temperature field analysis is re-performed until the temperature field analysis result meets the second preset condition.

4. The method of designing an engine exhaust gas temperature based on an optimized water jacket according to claim 3, wherein, The step of, if the temperature field analysis result meets the second preset condition, dividing the water jacket into structures and constructing a 3D cylinder head finite element temperature field according to the structure division result, and performing heat balance testing and checking according to the 3D cylinder head finite element temperature field, comprises: The water jacket is divided into a cylinder body cooling water jacket, a cylinder head lower water jacket, a cylinder head upper water jacket, and an exhaust manifold cooling water jacket; Based on the 3D cylinder head finite element temperature field, the input heat composition entering the cylinder head is counted, and the input heat composition includes the heat of the cylinder head fire surface, the cylinder head exhaust port, the cylinder body hole, and the intake and exhaust valves, so as to calculate the total input heat according to the heat of the cylinder head fire surface, the cylinder head exhaust port, the cylinder body hole, and the intake and exhaust valves; Based on the 3D cylinder head finite element temperature field, the output heat composition flowing out of the cylinder head is counted, and the output heat composition includes the heat of the cylinder body cooling water jacket, the cylinder head lower water jacket, the cylinder head upper water jacket, and the exhaust manifold cooling water jacket, so as to calculate the total output heat according to the heat of the cylinder body cooling water jacket, the cylinder head lower water jacket, the cylinder head upper water jacket, and the exhaust manifold cooling water jacket.

5. The method of designing an engine exhaust gas temperature based on an optimized water jacket according to claim 4, wherein, The step of, if the temperature field analysis result meets the second preset condition, dividing the water jacket into structures and constructing a 3D cylinder head finite element temperature field according to the structure division result, and performing heat balance testing and checking according to the 3D cylinder head finite element temperature field, further comprises: The first error value is calculated according to the total input heat and the total output heat, and it is determined whether the first error value is less than a second preset error threshold; If the first error value is less than the second preset error threshold, it is determined that the 3D cylinder head finite element temperature field reaches a heat balance standard; If the first error value is greater than or equal to the second preset error threshold, the 3D cylinder head finite element temperature field is checked until the 3D cylinder head finite element temperature field reaches the heat balance standard.

6. The method of designing an engine exhaust gas temperature based on an optimized water jacket according to claim 5, wherein, After the checking is completed, the first heat transfer heat flow of the exhaust port wall surface in the 3D cylinder head finite element temperature field is extracted, and a 1D cylinder head thermodynamic model is established, so as to calculate the second heat transfer heat flow of the exhaust port wall surface based on the 1D cylinder head thermodynamic model, and compare and adjust the first heat transfer heat flow and the second heat transfer heat flow until the heat dissipation effects of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field are within a first preset error threshold, which comprises: From the 3D cylinder head temperature field calculation, the temperatures of the cylinder hole, the piston, the cylinder head combustion chamber, and the exhaust port wall surface are extracted, so as to define the wall surface temperature of the gas heat exchange in the 1D cylinder head thermodynamic model according to the temperatures of the cylinder hole, the piston, the cylinder head combustion chamber, and the exhaust port wall surface; The exhaust passage gas side in the 1D cylinder head thermodynamic model is discretized into a plurality of regular pipes, and each pipe is respectively assigned a temperature according to the temperature of each pipe obtained from the 3D cylinder head temperature field, and then a second heat transfer heat flow is calculated based on the 1D cylinder head thermodynamic model.

7. The method of designing an engine exhaust gas temperature based on an optimized water jacket according to claim 6, wherein, The step of discretizing the exhaust passage gas side in the 1D cylinder head thermodynamic model into a plurality of regular pipes, respectively assigning a temperature to each pipe according to the temperature of each pipe obtained from the 3D cylinder head temperature field, and then calculating a second heat transfer heat flow based on the 1D cylinder head thermodynamic model is followed by: The first heat transfer heat flow or the second heat transfer heat flow is calculated according to the following formula: Φ denotes the heat transfer heat flow, in W, k denotes the heat transfer coefficient, in W / (m 2 .K), and A denotes the heat exchange area of the exhaust passage wall, in m 2 , denotes the gas temperature, denotes the exhaust passage wall temperature; A second error value is calculated according to the first heat transfer heat flow and the second heat transfer heat flow, and it is determined whether the second error value is less than a first preset error threshold; If the second error value is less than the first preset error threshold, it is determined that the heat dissipation effect of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field is consistent; If the second error value is greater than or equal to the first preset error threshold, the wall temperature of the gas heat exchange in the 1D cylinder head thermodynamic model is increased or decreased according to a third preset ratio, and the heat dissipation effect of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field is re-evaluated until the heat dissipation effect of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field is consistent.

8. An engine exhaust gas temperature design system based on optimization of water jacket, characterized by, The system comprises: An exhaust passage water jacket optimization module is configured to determine a to-be-optimized region in the exhaust passage water jacket based on the cylinder head water jacket temperature field, perform area optimization on the to-be-optimized region, perform flow field analysis on the cylinder head water jacket after the area optimization, obtain an exhaust valve nose beam region flow rate according to the flow field analysis result, and determine whether the exhaust valve nose beam region flow rate is greater than a first preset flow rate threshold; A temperature field analysis module is configured to perform temperature field analysis on the optimized cylinder head water jacket if the exhaust valve nose beam region flow rate is greater than the first preset flow rate threshold, obtain a temperature field analysis result, and determine whether the temperature field analysis result satisfies a second preset condition; A thermal balance checking module is configured to divide the water jacket into structures if the temperature field analysis result satisfies the second preset condition, construct a 3D cylinder head finite element temperature field according to the structure division result, and perform thermal balance testing and checking according to the 3D cylinder head finite element temperature field; A thermodynamic analysis module is configured to extract a first heat transfer heat flow of an exhaust passage wall surface in the 3D cylinder head finite element temperature field after the checking is completed, establish a 1D cylinder head thermodynamic model, calculate a second heat transfer heat flow of the exhaust passage wall surface based on the 1D cylinder head thermodynamic model, and compare and adjust the first heat transfer heat flow and the second heat transfer heat flow until the heat dissipation effect of the 1D cylinder head thermodynamic model and the 3D cylinder head finite element temperature field is within a first preset error threshold. The verification module is configured to verify whether the engine exhaust temperature is higher than a first exhaust temperature threshold under a preset operating condition, and if the engine exhaust temperature is lower than or equal to the first exhaust temperature threshold under the preset operating condition, re-evaluate whether the optimized cylinder head water jacket temperature field has the to-be-optimized region, until the engine exhaust temperature obtained after iterative optimization is higher than the first exhaust temperature threshold under the preset operating condition, and output a final cylinder head water jacket temperature field.

9. The optimized water jacket based engine exhaust gas temperature design system of claim 8, wherein, The exhaust passage water jacket optimization module further comprises: The to-be-optimized region screening unit is configured to perform numerical simulation on the cylinder head water jacket temperature field of the target engine to obtain a safety coefficient distribution result, and screen a to-be-optimized region in the exhaust passage water jacket wall surface that meets a first preset condition according to the safety coefficient distribution result, the first preset condition being a region in the water jacket wall surface where the temperature is lower than a first preset temperature threshold and the safety coefficient is higher than a first preset safety coefficient threshold. The optimization execution unit is configured to obtain an area of the to-be-optimized region, and reduce the area of the to-be-optimized region by a first preset proportion to obtain an optimized to-be-optimized region.

10. The optimized water jacket based engine exhaust gas temperature design system as claimed in claim 9, wherein, The temperature field analysis module further comprises: The cylinder head temperature detection unit is configured to determine whether the cylinder head temperature is less than or equal to a second preset temperature threshold and whether the exhaust water jacket wall surface temperature is less than or equal to a third preset temperature threshold. The first determination unit is configured to determine that the temperature field analysis result meets a second preset condition if the cylinder head temperature is less than or equal to the second preset temperature threshold and the exhaust water jacket wall surface temperature is less than or equal to the third preset temperature threshold. The second determination unit is configured to increase the area of the optimized to-be-optimized region by a second preset proportion if the cylinder head temperature is greater than the second preset temperature threshold and / or the exhaust water jacket wall surface temperature is greater than the third preset temperature threshold, the second preset proportion being less than the first preset proportion. The temperature field analysis is performed again until the temperature field analysis result meets the second preset condition.

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